Hello Zach ,
I try to help this user he was install 2.4 for the first time and he have this problem , then i ask his to upgrade to 2.4.1 i think this may fixed after the upgrade but the problem still there !!
I reverted the "adv_gallery_showimage" template to the default but the problem is still there , by the way the default style do not have this problem and this problem is shown only in the gallery !! any idea ??