In shotwell, it is possible to set external editors that can be used to edit pictures. One can choose from a list of installed programs like e.g. Gimp and ImageMaverick on my system.
However, I would like to use Adobe Photoshop, which I just managed to install using PlayOnLinux. I already created a *.desktop file and it runs perfectly when I start it from the Unity launcher.
My problem is that Photoshop does not show up as possible choice for an external editor in shotwell. I tried modifying the *.desktop file after studying those of gimp and ImageMaverick but could not get it to work. In particular, I set the Category to Graphics and the MimeType entry to the same as for gimp.
Is there any way I can make shotwell add Photoshop - or any program for that matter - to the list of external editors?
Any hints would be much appreciated!