Description
The rule determines if an alternative description for the image (alt attribute) contains a filename. Basically, it searches for filenames with the following extensions:
apngavifbmpgifjpegjpgpngsvgtiftiffwebp
Context
Quite often, the image contains an alternative description using only a filename. This doesn’t help to understand the image context for screen reader users as well as for search engines. Therefore, we recommend providing a meaningful description of what the image is about.
How to fix it
Avoid setting alt attribute with a filename for the image and instead provide a meaningful description of what the image is about.
Standard
Accessibility, Best Practices, Sitelint