Social Security Administration Guide: Alternate Text for Images

Tool-tips on images

Tool-tips are supposed to be tips to help you use a tool. A tool is a control or widget. Something like “Play”, “Stop” or “Pause”. A link to a website, however, is not a tool; it is a link to a website. The information that users need to know should not be ‘hidden’ in a tool-tip. Often tool-tip style use for alt-text is done because of a lack of space, or because designers think the minimalist design looks less cluttered. For users with low vision who need to zoom in on the screen, tool-tips can be particularly difficult because as the mouse moves, the tip moves, making it difficult or impossible to track visually.

It’s a tool-tip, and essential information is hidden from normal view.