https://askubuntu.com/questions/774490/what-is-an-appimage-how-do-i-install-it
It appears that all you have to do is
chmod +x application.AppImage
and then you can run the image directly
./application.AppImage
Example:
bob@localhost:~$ chmod +x Downloads/Vysor_2.2.1.AppImage bob@localhost:~$ Downloads/Vysor_2.2.1.AppImage