Analysing Image Alt Text | Screaming Frog Club

Brief

How to find images without alternative text, or with overly long alt text, using SEO Spider’s Images and Image Details tabs. See also how to trace the pages that use each image.

Alt text

Alt text (alternative text) is used in a website’s HTML to describe an image in words.

It’s essential for web accessibility (for blind and partially sighted people) and provides alternative text if the image can’t be loaded.

Search engines use it a lot to understand image content, although its role has diminished now that Google interprets images on its own with artificial intelligence.

Further reading: HTML img alt attribute – W3Schools.

Finding images without alt text

Let’s go through the main steps to find images missing this attribute.

1. The Images tab

After crawling a subdomain, click the 1Images tab, which lists every image URL, its size and the number of IMG inlinks.

Screaming Frog Images tab with the list of image URLs, their size and IMG Inlinks — The Images tab lists every image found in the crawl.

2. Image Details

Click the Image Details tab in SEO Spider’s bottom window to see all the source pages that reference the image (the ‘From’ URL) and the alt text of each image element found, plus a preview on the right.

Screaming Frog Image Details tab with the pages using the rand.jpg image and their alt text — Image Details shows which pages use the image and with which alt text.

In the example above, four pages of the Screaming Frog website (listed in the ‘From’ column) use the same image (https://www.screamingfrog.co.uk/wp-content/uploads/2014/03/rand.jpg).

The inconsistency is that only one of the four HTML pages has alt text (‘rand’); the others are empty, meaning they lack alt text.

Images can be referenced by many different URLs and so have many different alt texts to optimise. Even if the image appears on several pages, those pages likely have different search intents, so when optimising I recommend writing different versions of the alt text to fit each context.

3. Missing Alt Text and Missing Alt Attribute

Use the Missing Alt Text or Missing Alt Attribute filters.

The ‘Missing Alt Text’ filter includes every image that has an alt attribute that’s empty or only contains white space.

<img src="screamingfrog-logo.jpg" alt="" />

The ‘Missing Alt Attribute’ filter includes images with no alt attribute at all.

<img src="screamingfrog-logo.jpg" />

Screaming Frog keeps these two filters separate because of decorative images, which as a best practice should have empty alt text rather than none, so they don’t cause problems for screen readers. A good practice is to serve decorative images as CSS background images.

Screaming Frog Images tab with the Missing Alt Text filter active — The Missing Alt Text filter isolates images with an empty alt.

Exporting the data

Once collected, you can export the data for each filter directly from the tab, or in bulk with 1Bulk Export›2Images›3Images Missing Alt Attribute & Text Inlinks.

These files also show the source pages, the image paths and the alt text, for a more accurate view of any issues.

Screaming Frog Bulk Export › Images menu with the Images Missing Alt Attribute & Text Inlinks item — The export puts images without alt text and the pages containing them in one file.

When optimising images it can be very useful to export every resource (including those missing alt text) in one go from 1Bulk Export›2Images›3All Images.

Screaming Frog Bulk Export › Images › All Images menu — All Images exports every image with its alt text.

Images not found

Some images may not be discovered by SEO Spider. In most cases it’s because robots.txt blocks them, or they’re loaded with JavaScript or CSS (such as a CSS ‘background-image’).

In the first case you can customise the robots.txt from 1Configuration›2robots.txt›3Custom; in the second, enable JavaScript rendering in 1Configuration›2Spider›3Rendering and recrawl.

Crawling Alt Text.