Yes. Edits that add image descriptions (or in this case provides a transcript of text in an image) add accessibility without changing the core content of a post and should be accepted.
That said, this particular edit has been accepted, and it appears that the reject vote was a simple mistake.
Titles should be straight forward and in the form of a question. Your suggestion:
What game is this from? (probably an old Japanese arcade platformer)
There are two problems here. First, "probably" should not be in the title. What if it's wrong? So the whole phrase should go.
Even without the probably, this still isn't in the form of a question: ...
I'm marking this as status-completed, since the bulletin has undergone some network-wide changes a while back. It currently looks like this (it's from MathOverflow, but aside from the favicon it would look the same on Arqade):