Ubuntu - Add a Flameshot Icon

All applications' desktop entries can be found in /usr/share/applications.

You can create a desktop entry under ~/.local/share/applications to make your own icon.

zzh@ZZHPC:/usr/share/applications$ sudo cp org.flameshot.Flameshot.desktop ~/.local/share/applications
zzh@ZZHPC:/usr/share/applications$ cd ~/.local/share/applications
zzh@ZZHPC:~/.local/share/applications$ sudo chown zzh:zzh org.flameshot.Flameshot.desktop
zzh@ZZHPC:~/.local/share/applications$ mv org.flameshot.Flameshot.desktop ZFlameshot.desktop
zzh@ZZHPC:~/.local/share/applications$ vi ZFlameshot.desktop 

Change the 'Exec' line for [Desktop Entry] to "Exec=/usr/bin/flameshot gui --delay 500".

Modify the value of 'Actions' for [Desktop Entry], deleting 'Capture;'.

Delete the [Desktop Action Capture] part.

Delete all the 'Desktop Action' parts, leaving only the [Desktop Entry].