I have downloaded the newest Cura Slicer Software as appimage and wanted to start it through my gnome favourites. To do so you need to create a .desktop file that refers to the appimage
[Desktop Entry] Name=Cura Comment=Cura Slicer Exec=/home/apunkt/Downloads/Ultimaker_Cura-4.11.0.AppImage Icon=Acetino2 Terminal=false Type=Application Categories=Printer;
To change the icon you can choose any icon that is stored under
just by naming it.