Dear all,
The desktop integration icons for The Linux AppImage are missing.
I believe the fix is as simple as adding the icon alternatives for the missing folders below while building the *.AppImage:
(AppImageRootBuildDirHere)/usr/share/icons/hicolor/16x16/apps/(iconFileAsInDotDesktopFIleWithExtension)
(AppImageRootBuildDirHere)/usr/share/icons/hicolor/32x32/apps/(iconFileAsInDotDesktopFIleWithExtension)
(AppImageRootBuildDirHere)/usr/share/icons/hicolor/48x48/apps/(iconFileAsInDotDesktopFIleWithExtension)
(AppImageRootBuildDirHere)/usr/share/icons/hicolor/64x64/apps/(iconFileAsInDotDesktopFIleWithExtension)
(AppImageRootBuildDirHere)/usr/share/icons/hicolor/128x128/apps/(iconFileAsInDotDesktopFIleWithExtension)
(AppImageRootBuildDirHere)/usr/share/icons/hicolor/256x256/apps/(iconFileAsInDotDesktopFIleWithExtension)
(AppImageRootBuildDirHere)/usr/share/icons/hicolor/512x512/apps/(iconFileAsInDotDesktopFIleWithExtension)
I believe this should fix the icon for any desktop environment.