Adam was unable to convert the rebound after being hauled down by a defender, but while Gallagher has acknowledged that the Scot was fouled, he has insisted that the initial penalty should not have been given.
Gallagher told Sky Sports News: "I don't think it is a penalty at all. If anything, I think Jese touches Stephens first, and there's not enough from him to go down.
"Regarding the rebound, I actually thought it was a foul, but I can understand why the referee doesn't give it. It's so, so difficult to see. The referee is not going to give a penalty, because he can't be convinced."