My comment above should be taken with a grain of salt.
broken
It works in many cases. From a privacy/security standpoint, it is a nightmare since any program can just access all other windows. Multiple monitor setups with different scaling don't work at all. …
Maybe your picture was rotated by changing its metadata (it was not reencoded in a new direction) and pict-rs didn't handle that metadata correctly. If I find the time, I'll try it myself.
Containerized applications are applications run in isolated packages of code
My main point is that a running AppImage isn't isolated, it can access and modify any file that the user has the permission to. So theoretically, an AppImage could read and upload your ssh keys or put rm -rf ~ in your .bashrc.
A Flatpak app on the other hand needs to either declare specific permissions in its manifest if it wants to e.g. access your home directory or use xdg-desktop-portal to ask for a permission at runtime. This can help when running proprietary/untrusted software or if you want to control what a program can do and what not.
A more popular example are Android apps which are executed in a strict sandbox and need to ask for permission if they want to read your images, access your microphone etc.
Fuck x.com. All my homies use wayland.social.