The Photo Gallery, Sliders, Proofing and WordPress plugin before 4.5.0 does not verify that the user acting on an image owns the gallery it belongs to, allowing users granted its gallery-management capability by an administrator to delete, copy and re-tag any image on the site, including images in galleries belonging to other users.
The Photo Gallery, Sliders, Proofing and WordPress plugin before 4.5.0 does not check that a user holds its options capability before saving image sizing settings, allowing users granted only its gallery-management capability by an administrator to change settings that apply across the whole site.