Hey Alexis!
You'll need to delete the "persistent" file both in the game folder and in your the Renpy folder.
Both are located in AHITR\Game\Saves and AppData\Roaming\RenPy\AHITR (both in the main folder here and "sync")
On Android you'll find it in "ahitr_storage" and inside the "sync" folder.
This should give you a clean gallery!