Image 'alt' attribute, how to bulk check it

Visual SEO Studio tutorial: How to find all images with no 'alt' or 'title' attribute.

There many repetitive task SEO professionals have to do. One of them is searching for image tags with no alt or title attribute.

What the "alt" attribute is

The "alt" attribute (often erroneously referred to as "alt tag") is an HTML attribute of the IMG tag. Its purpose is providing an alternative text for the image in case the image were not downloaded, and to provide a text for screen readers used by visually impaired people.

<img src="iceberg.png" alt="an iceberg" />

Unless the image is purely decorative and does not add to the content (is it really worth having it?) the "alt" attribute should be present and not empty. A proper description also helps search engines better rank your assets in image search.

How to bulk check the "alt" attribute

Luckily Visual SEO Studio makes the task easy: the Custom Filters functionality, a powerful SEO oriented query engine the program is equipped with, comes to the rescue.

Assuming you already crawled the site you want to check, open "Custom Filters" and create a new filter.
In the drop down combo box listing all queryable page properties, within the "Images" group select the "Image alt attribute" property and choose the "Is null or empty" operator.

Custom Filter: all pages with images without alt attribute
Custom Filter: all pages with images without alt attribute

Apply the filter to your crawled data (the saved "crawl session"). In the Tabular View showing the results, select the "Page Images" bottom panel and sort the "alt attribute" column to see all images without alt attribute at a glance.

Using the Page Images bottom pane
Using the Page Images bottom pane (click to enlarge)

Through the "Page Images" panel you can also jump directly to the selected <img /> tag, both in DOM and in HTML code of the page.

You can see where the image is in HTML and DOM views
You can see where the image is in HTML and DOM views (click to enlarge)

Remember to save the custom filter so you can use it every time you need to repeat this check.

The same procedure allows you to check for image titles, this time selecting the "Image title attribute" property.

Note: the "title" attribute (not to be confused with the title tag in the page HTML head) is not specific of the IMG tag; browsers normally use it to show a tooltip. In the case of images, it is common practice to set it the same as the "alt" attribute, even if not mandatory.

As you can see, it is possible to combine two properties in logical OR to extract, for example, all pages with images without alt or title attributes.

Custom filter rows in combined OR logic
Custom filter rows in combined OR logic

Like all grids in Visual SEO Studio, you can customize columns order and export data to Excel or CSV file in one click.

What to do next

Once you have located all images missing the "alt" attribute, it's time to populate them at best.
There are some rare case where you might want to leave them missing or blank, but in most cases you should write them with a one line sentence describing what the image is about.

A few recommendations:

  • User Experience comes first. Keep the text clear and concise.
  • Search engines use the alternate description to rank graphic content in "image search". Don't try to trick them telling the image is something it's not, they are smarter than you might think. Most of all, don't stuff keywords. A well thought keyword may fit in the text, but use them with wit and moderation.

So what are you waiting for? Go to check for "alt" attributes with Visual SEO Studio!