Images of Text asks teams to use actual text styled with CSS rather than a picture of text, except in cases like logos or where a specific visual presentation is essential to the content. Real text can be resized, reflowed, recolored by the user, and read aloud accurately by a screen reader, none of which a flattened image can do.
This shows up most often in marketing banners, pricing graphics, and social-style quote images embedded directly in page content. The fix is usually straightforward: rebuild the graphic as styled HTML text, or at minimum supply a complete, accurate text alternative.