User blog comment:SEOkitten/The Importance of Images/@comment-1038387-20151026190446/@comment-26321732-20151028155322

File page descriptions are often missing or limited and, although these can encourage search engine users to click on the page in search results, the greatest value is in the image names themselves (in large part because the file name becomes the alt text in absence of a manual alt tag).

Numbers at the end of a relevant, human (and search bot) readable image name are often needed to distiguish between different images of James Bond, so that is not a problem for search engines.