Ok, I’ve just verified: passing a file name to the appimage works perfectly. Moreover, when a RAW file is passed, PhF gets opened automatically as it should.
Now we have to figure out how to integrate this with the file managers… meanwhile, here is the appimage version that accepts input files: Dropbox - gimp-2.9.5-20160823.glibc2.15-x86_64.AppImage - Simplify your life
Thanks!