Selected answers from the Dumb SEO Questions G+ community.
Dave Collins: Not as such. You can use ALT text and title text. Nothing like a description though.
Michael Martinez: You are supposed to do that in the IMG element, although you can wrap the image with a DIV and add a caption. If your goal is improve the listing in image search those are the steps you need to take. Also, use a meaningful image file name that can be parsed (e.g., "some-descriptive-phrase-as-image-name.jpg" instead of "keyword.jpg").
Alan Bleiweiss: And you can wrap the image in Schema structured markup as well. http://schema.org/image