1. Photo & Video
  2. Digital Asset Management

Caption, Description, Title, ALT: How to Add Semantic Information to Images

Read Time:16 minsLanguages:

Have you ever looked at a photograph found in an old photo album and wondered who was pictured? Or looked at a documentary photograph and questioned when and where the photograph was taken? We might be pretty good at remembering the details about our own photos, but our memories won’t be as complete years later and it’s a given that other people won’t know the details if we don’t pass them on. While it may be true that pictures can say a thousand words, what’s said is usually not worth very much without contextual information.

Adding context to a photograph is as important as naming it clearly, filing it logically, and backing it up safely. In this article, we’ll look at the different types of information that can be added to photographs, how that information is used, and what we need to consider when adding that information to our own photos.

Hands of an unidentified person working on an unidentified craftHands of an unidentified person working on an unidentified craftHands of an unidentified person working on an unidentified craft
Without some information, it’s difficult to know what’s going on in this photo. What’s being made? Why? By whom? (Photo by Dawn Oosterhoff)

How To Use Metadata Fields to Add Information to Digital Images

In this article,we won’t look at the specifics of how to add metadata to digital images. However, the suggestions and tips I offer assume that some of the contextual information will be added to an image’s metadata using the file management application in your computer’s operating system or using digital asset management software.

It’s pretty rare that you will need, or even want, to add all information to all photos. As always, start by thinking about the purpose of your photos. If you’re submitting a photograph to be published in a newspaper or to be sold as stock, you’ll need to be comprehensive with the text you add. In contrast, a series of portraits may not need much more information if the filenames already identify the subject.

Computer dialogue showing metadata fieldsComputer dialogue showing metadata fieldsComputer dialogue showing metadata fields
The standard metadata fields that are accessible with most software include Title, Description, and Keywords. These same fields can also be identified as Headline, Caption, and Keywords.


Before thinking about Descriptions, Captions, ALT text, and Titles, add keywords to your images if you haven't already done that. Keywords are basic and essential textual information, which should be added to any photograph you intend to use or return to again. If you’re not already familiar with using a controlled vocabulary to tag your images with keywords, take the time to read another article in our digital asset management series: Using a Controlled Vocabulary to Organize Digital Photographs.


After tagging an image with keywords, move on to the easiest—and from an archival perspective, most important—information to add to an image: descriptions. Captions and descriptions are often considered to be the same thing, but they are not, even though they occupy the same field in standard metadata fields. Captions are meant to be read by someone viewing the image whereas descriptions contain basic information that is meaningful to anyone working with the images. Further, a well-written description provides the information needed for the rest of the metadata fields. Archivists love getting comprehensive descriptions because almost everything else to be said about a photo can be drawn from a good description.

Because descriptions are meant to be functional, what you write is more important than how you write it. When writing descriptions, think about an archivist going through your photographs twenty-five years from now. Will the archivist be able to correctly identify your photo based on the information you’ve left in the description? To ensure you record everything that is relevant, use the five Ws of journalism—who, what, when, where, and why—as your guide. You won’t need to answer all five Ws for every photo, but it’s a great prompting device.

  • “Who” names the subject of your photo, whether person, place, animal, or other. For example, the “who” could be the Burj al Arab Hotel, Uncle Leonard, or an animal.

Monarch butterfly sitting on a leafMonarch butterfly sitting on a leafMonarch butterfly sitting on a leaf
The “who” in this photograph is a Monarch butterfly. (Photo by Dawn Oosterhoff)
  • “What” describes the story in the photo. To answer this question, consider what is going on in the photograph. For example, is the photo about a relationship between the people depicted? A winning goal in a football game? A record of a sight that moved you?

  • “When,” obviously, provides information about when the photo was taken. Unless the information has been stripped, the calendar date will be recorded in a digital image's metadata. What won’t be included is information about the day or event. Think about time broadly with this question. For example, is it someone’s birthday? An anniversary? Celebration of a business opening?

  • “Where” provides details about the location depicted in the photo. Again, the obvious information may be recorded in the image’s metadata as GPS coordinates. But, once more, think broadly. GPS coordinates will identify a city and even a street, but they won’t capture, for example, that the photo was taken in your sister’s home or in the CEO’s office.

Exterior of Canterbury Cathedral as seen from a residential windowExterior of Canterbury Cathedral as seen from a residential windowExterior of Canterbury Cathedral as seen from a residential window
The subject of this photo is Canterbury Cathedral, obviously taken in Canterbury, England. However, when asking “where,” it’s important to note that this photo was taken from a guest room in the gate to the cathedral. (Photo by Dawn Oosterhoff)
  • “Why” asks for information about the purpose of the photo. Sometimes, the answer to “why” can go without saying. A photo taken of your grandmother blowing out candles on her birthday cake is obviously about celebrating your grandmother’s birthday. The answer could also be straightforward, but very relevant. For example, photos taken at a corporate event will tell different stories if they were taken for the corporation’s annual report or for the employees’ social media site. And don’t be surprised if there is no answer to “why” or the answer is philosophical.

The five Ws of journalism are often followed by the question, “How?” Information about how the photo was taken may be relevant information for you to include in your description. If shooting digitally, a great deal of information about the “how” will already be recorded in the metadata—exposure settings, focal length, and so on. But if it’s relevant, for example, that you used a butterfly lighting setup, the description offers you the chance to capture that information.

Impressionistic photo of poppiesImpressionistic photo of poppiesImpressionistic photo of poppies
The subject of this photo is poppies, taken at Rideau Falls Park, Ottawa. But why and how I took the photograph are what I want to record in the description. I took the photo with intentional movement and a deliberately moistened filter in an attempt to capture how I was seeing the poppies in the early morning mist from the falls. (Photo by Dawn Oosterhoff)

A final note about descriptions: don’t use them as a replacement for keywords. Tagging images with keywords is a methodical process that aids searching. Keywords rarely provide enough information to fully identify a photo. At the same time, there may be information that you wanted to include with keyword tagging, but the information does not belong in a controlled keyword vocabulary. Put that information in the description!

If you’ve included everything that’s relevant in a photo’s description, writing the following forms of information will be easier.


Captions are mini-stories that provide viewers with interesting and relevant information that they can’t get from just looking at the photo. As I mentioned above, unlike descriptions, captions are meant to be read by others. In fact, in journalism and print publications, only headlines get more attention than captions.

A well-written caption draws the viewer further into a photograph. Viewers look at a photograph first, then read the caption under the photo. If the caption provides the viewer with interesting and relevant information, the viewer will look again at the photograph and, ideally, see something new. This visual trip from photograph to caption and back to photograph is called a loop. In journalism, the loop is meant to entice the viewer to dig in a little further and read the whole story accompanying the photograph, but for our purpose, understanding the loop between photo and caption is sufficient.

You may never need to write a caption, but knowing how to write captions is a good skill to have. Attaching a caption to a photo might be the feature that sells a photograph to a publication. And if you ever put together an album of your photos, knowing how to add well-written captions can transform your album from a collection of pics to a treasured narrative.

Writing captions is an art form similar to writing Haiku poetry: once you know the few basic rules, you just keep practising and refining until the art comes easily. If you have an interest in narrative or if you’re planning to sell your work as a journalist, you’ll need to learn more than what I’ve included here, but the following rudiments will get anyone started with caption writing.

I’m going to use the following photo as an example to describe how to write a caption.

Soldiers and a young boy kneeling to place poppies at military gravesitesSoldiers and a young boy kneeling to place poppies at military gravesitesSoldiers and a young boy kneeling to place poppies at military gravesites
Richard Lawrence Photography. Used with permission.

1. Take a good look at the photo you are writing the caption for. What is it that you want or need to communicate with this picture? How is the photograph relevant to the other photographs in the collection and to the rest of the text, if any, that will accompany the photograph? Jot down the key words and ideas. These are your notes, so don’t fuss about grammar or style yet.

Remembrance Day—teaching a child the importance of the day and the ritual of placing poppies on soldiers’ graves

2. Now, using the words and ideas you jotted down, write a short, declarative sentence that sums up what’s happening in the photograph and identifies the people and place. A photograph stops a moment in time, so use the present tense for this first sentence.

Sergeant Bonhomme (rear) explains the practice of placing poppies on soldiers’ graves to Army Cadet Goodfellow and six-year-old Timmy.  

3. Write a second and, if needed, third sentence to provide the rest of the information viewers need to understand what they are looking at. These sentences provide context and background for what happened, so typically, you’ll use the past tense.

It’s tradition after Remembrance Day services for soldiers to remove the poppies from their uniforms and place them on soldiers’ gravesites. The tradition was being carried out after Remembrance Day services on Wednesday at the National Military Cemetery at Beechwood Cemetery in Ottawa.

4. Add the credits.

Richard Lawrence Photography

You can learn more about writing good captions by analyzing captions you read in newspapers and magazines. Captions may be difficult to master, but they can be a rich, important contribution to a photo.

ALT Text

ALT text is information you add to an image posted on the web. ALT text is only relevant when photos are posted to the web, but when photos are posted to the web, ALT text is important because it provides information about an image to anyone or anything that can’t see the image.

The most important function of ALT text is to provide information to viewers with visual impairments. People with low vision use screen readers that read out the text on a website. When a screen reader encounters an image, it will read aloud the ALT text attached to the image. Viewers who have a slow internet connection will also read the ALT text if the images can’t be downloaded.

Internet search engines are also unable to read images. Instead, the search engines rely on ALT text to gather information about images and about websites that consist largely of images. ALT text is your opportunity to provide information to search engines that bring visitors to your website. ALT text also improves the visibility of your images in image searches.

What you write in ALT text depends upon the context for the photo. For example, I would describe the following photograph in different ways, depending upon how I was using the image.

Photographer using a hotel sitting room to take a group photoPhotographer using a hotel sitting room to take a group photoPhotographer using a hotel sitting room to take a group photo
Richard Lawrence Photography. Used with permission.
  • For a photography article, I’d write, “A setup for photographing a group, using two softboxes, a speedlite, and a reflector.”
  • For an article about the hotel, I’d write, “The Alcove, with dark wood, transformed from a sitting room to a photography studio.”
  • If I were putting the photograph on my website to promote my business, I’d write, “Photographer Dawn Oosterhoff working onsite at the Chateau Laurier, organizing a group for a formal photograph.”

What you do not write is a list of keywords or tags. Imagine being a visitor with a visual impairment listening to a screen reader recite a litany of meaningless information! Hashtags and abbreviations or codes are also meaningless and potentially annoying. Instead, write a short statement—about the length of a tweet—describing the purpose the image is fulfilling. There’s no need to add “Photo of … ” or “Image about … ” to your description; the HTML on a website will take care of that.

Unfortunately, as important as ALT text is, you can’t embed ALT text in an image’s metadata field except for recordkeeping. For now—there is a push for change—you must manually add ALT text each time you upload an image to the web. Usually, an ALT text option appears in common image uploaders either as “ALT” or “description.”


A title is the shortest piece of information you’ll add to an image, but it can also be the most difficult to write. Thankfully, titles are not often required. You will want to add a title to your image if you need to provide a reference to the photo, distinguish individual photos in a collection, or add meaning to your photographic intent.

If you need a straightforward reference for your photo, use a straightforward title that captures the most important aspect of the photo. For example, I might name the following photographs, “Mist on Arowhon Lake 1” and “Mist on Arowhon Lake 2.”

Morning mist blowing over the swimming area of a lakeMorning mist blowing over the swimming area of a lakeMorning mist blowing over the swimming area of a lake
Dawn Oosterhoff
Morning mist blowing over sailboats tied up at a dock on a lakeMorning mist blowing over sailboats tied up at a dock on a lakeMorning mist blowing over sailboats tied up at a dock on a lake
Dawn Oosterhoff

You may want to be more subjective, however, if you are using a title to add context to your photograph, to nudge viewers in a certain direction when viewing the image, or to help sell an image. If this is the case, jot down the words and phrases that come to mind as you think about the most important aspect of your image. Use those words and phrases in combination with the following advice to come up with a title:

  • Use short, common, specific, and powerful words to express the main idea of your photo’s story.
  • Avoid titles that contradict your photo’s story or will limit viewers’ interpretation of the photo. Leave room for viewers to see something more or other than what you imagined.
  • Use a title that draws viewers in. Cleverness, humour, puns, and clichés can often drive viewers away. Showing off will also drive viewers away. If your title will make a viewer groan, don’t use it. Use a play on words only if it contributes to meaning.
  • Think about how those in the photo or viewers looking at the photo will interpret the title. A title may seem clever to you but smack of ridicule to someone else. A friend or colleague might be able to help you gain perspective if you’re not sure.
Woman pushing a proud-looking man in a wheelchairWoman pushing a proud-looking man in a wheelchairWoman pushing a proud-looking man in a wheelchair
I needed to provide a title for this photo when I submitted it to a juried competition. I named it “Driver’s Seat” in order to nudge the viewer to think about who is in control of the excursion in this photograph. Because I didn’t want to limit how viewers would interpret the relationship between the two subjects, I was careful not to identify a subject, activity, or role in the title. (Photo by Dawn Oosterhoff)

Summary: What Information to Use When

We’ve looked at a four ways to add information to a photo, in addition to adding keywords. Each bit of information serves a different purpose and thus, has different characteristics. The following table provides a summary that you may want to reference when you’re working on your images.



Key Principles


Tag an image with words that will help you to later locate that and similar images with a search.

Keywords come from a controlled vocabulary to limit variability and improve search results.

Every photo you intend to use or look at again should be tagged with keywords.


Provide meaningful information about the photo that will help anyone working with the photo now or later.

The information is functional: what you write is more important than how you write it. Include all information relevant to correctly identifying the photo years later.

Add descriptions to any photo you think will be relevant years later. Use the five Ws as a prompt to identify what information to include.


Provide viewers with mini-stories that help to draw viewers into the photo and see more than they might have seen on first look.

The information sums up what’s happening in the photograph, identifies the people and place, and provides any other information necessary to understand the photo. Captions also include any relevant credits.

Use captions to complete a photo’s story. Don’t restate what is already obvious. Add to photos that will be submitted for use in newspapers and magazines. Also add captions whenever you wish to create a rich narrative with photos.

ALT Text

Describes an online image to viewers who can’t see the image and provides search engines with content to drive viewers to the website.

A short statement describes the image. What is included in the description depends upon how and why the image is being used.

Add ALT text to any image you post on the internet. Always think of the human viewer first. Do not fill ALT text with a string of keywords, hashtags, or abbreviations.


Used to identify a photo or to distinguish one photo from another in a collection. Also used to add meaning to the photographic intent.

A short, specific, functional description or a subjective description that enhances the interpretation of an image.

Provide titles only when needed. Express the main intent of the image but leave room for viewers to bring their own interpretations. Use humour, clichés, and other clever techniques sparingly.

Adding textual information to photos can be both a functional and artistic tool. At minimum, add keywords to any image you wish to return to in the future. Also add descriptions sufficient to identify any photographs that you or someone else consider worth keeping. That’s good data management. And when the need arises, use the principles we’ve discussed to add captions, ALT text, or titles.

If you’d like to practice adding textual information to a photograph, use the comments below to suggest what you would write for one of the five bits of textual information for the following photograph. (Make up information if you need to.) It will be interesting to compare and discuss different responses!

Dog barking at a swan in the waterDog barking at a swan in the waterDog barking at a swan in the water
Dawn Oosterhoff
Looking for something to help kick start your next project?
Envato Market has a range of items for sale to help get you started.