A "photo finder/identification" (who/what/when/where/why/etc) type of question is a research request. You close it by casting a close vote on the question (most preferably) or flagging for moderators attention.
However, there have been some exceptions:
- This question: In addition to identification, this question asks about the history of said photo (and sports history is on-topic). It's clear that more effort was put into the question (and answer) than to say "I think it's [x]", "Find this [y]", or "Where can I look for [z]" as such statements were the motivation for having source/research requests off-topic on Sports SE.
- Autograph identification questions have been received well here and are asked on an occasional basis. To make such questions reasonably scoped, background information is suggested (eg, when/where/how the ball was obtained, which team(s)/game said autograph originated from, what time period the ball was signed in, etc. as applicable and available).
In summary, if the question is simply asking us to identify something (outside of an autograph) and nothing more, it's a good bet it's off-topic. See this for more information on research requests.