Baseball-reference [
http://www.baseball-reference.com/re...d=thomps001ear ] does have an Earl Thompson
pitching as a teenager for Dover in the Class D Eastern Shore League in 1948 and for Schenectady in the Class C
Can-Am League in '49.
No idea if it's the same guy in your photo (no pic at Baseball-reference, so their Earl Thompson might be black, white, or green).
Minor-league records at Baseball-reference are unfortunately incomplete, so even if it is your guy, he could have played for
other teams not listed there, including late-era Negro League teams.