The OP said the other does match. Please, check the OP last statement. "..The problem is I have a file named "test.jpg" and another called "testl.jpg" and the expression only picks up the first one. Other than that, it works fine..."
If you tell me, I'll forget.
If you show me, I'll remember.
if you involve me, I'll understand.
--- Author unknown to me
Unless I'm mistaken and missed some un-commented update, you added a '.+?' to the beginning of the OP's regex. So I still don't understand why you think that will match any better, as the '.+?' is superfluous.