Captions and the Work They Do

Why captions get read

People skim. They look at images, and the text immediately beneath an image is read as part of looking at it rather than as reading.

Which means a caption reaches an audience that includes everybody who read the surrounding text plus a substantial number who did not.

For a business site that makes captions valuable space, and they are routinely left empty or filled with a filename.

Caption and alternative text are different things

Worth settling because they get conflated and they serve different purposes.

A caption is visible to everybody. It adds information the image does not convey and it is part of the content.

Alternative text is not visible. It describes the image for somebody who cannot see it, and for a screen reader it stands in place of the image.

They should not be identical. If the caption already says what the photograph shows, alternative text repeating it means a screen reader user hears the same sentence twice.

Where a caption fully describes the image, the alternative text can be brief or the image marked as decorative. Where the image carries information the caption does not, the alternative text does that job.

What a caption should say

Not what is visible. What is not.

• The context, such as what the job was or what condition it was in.
• The constraint, meaning what made it difficult.
• The detail worth noticing, which a non-expert would miss.
• The outcome, where the photograph shows a stage rather than a result.
• The timeframe, since duration is invisible in an image.

The third is the most useful for a trade. A photograph of finished work looks like finished work; a caption pointing out the flashing detail, the joint placement, or the repair underneath tells the reader what they are actually looking at and why it matters.

That is the same argument as explaining invisible work, delivered in the place people actually read.

What not to write

Descriptions of the obvious. A photograph of a bathroom captioned bathroom renovation adds nothing.

Filenames or camera references, which some systems insert automatically.

Marketing language. A caption saying quality craftsmanship is filler in the one place readers are paying attention.

Anything identifying a customer's property without permission, including street names and house numbers.

That last one applies to captions specifically, because a caption naming a neighbourhood is more identifying than the photograph frequently is.

Length

One or two sentences.

Long captions stop being captions and become body text in the wrong place. If there is a paragraph to write, it belongs in the article and the caption should point at it.

The exception is a technical photograph where the explanation is the point, in which case a slightly longer caption is doing real work.

Whether captions help with search

Modestly and indirectly, and worth being honest about.

Text near an image contributes to understanding what the image and the page are about, which is a genuine if small effect.

What matters more: a descriptive filename, meaningful alternative text, and the surrounding content. A caption is part of that context rather than a lever on its own.

Writing captions for search rather than for readers produces the usual result, which is text that serves neither.

Where captions matter most

Three places on a small business site.

Before and after pairs, where the caption establishes what changed and what the constraint was. Without it a reader sees two photographs and infers what they like.

Process and detail images, where the caption is the entire reason the photograph is there.

Team photographs, where names and roles are the information and their absence is a wasted image.

Product photographs on a store are the other case, where the caption can carry the detail that stops a return: scale, material, or what is included.

The practical habit

Write the caption when the photograph is added, not later.

The context is available at that moment and it is gone in three months. A library of uncaptioned images is a library somebody will have to guess about, and guessing produces the descriptions of the obvious that make captions worthless.

Recording a line about each photograph when it is taken solves this at the source, alongside the other details worth capturing on site, which is described in the photographs that actually persuade.

Frequently asked questions

West Coast Media Solutions Inc. provides web design, web development, hosting, digital marketing, and business consulting to organisations across Canada, drawing on more than twenty-five years in the field.