It has been a while since I have noticed any questions about the DSG (dreadful scrolling gallery) beloved by sellers and hated by many buyers. At least yours is at the bottom which means I would not close your listing without getting down that far.

I don't know of any way you could create a gallery, scrolling or otherwise, that automaticaly repopulated when you got more stock other than one that linked to your total listings, maybe somebody else will have an idea.