Wikipedia:Manual of Style/Captions

Wikipedia guideline on image captions / From Wikipedia, the free encyclopedia

A caption is text that appears below an image.[lower-alpha 1] Most captions draw attention to something in the image that is not obvious, such as its relevance to the text. A caption may be a few words or several sentences. Writing good captions takes effort; along with the lead and section headings, captions are the most commonly read words in an article, so they should be succinct and informative.

Not every image needs a caption; some are simply decorative. Relatively few may be genuinely self-explanatory. In addition to a caption, alt text  for visually impaired readers  should be added to informative (but not purely decorative) images;[1][2][3] see Wikipedia:Alternative text for images.