I have exactly same task like here:
Windows 7 - Add shell command for .png file
But this solution doesn't work in Windows 8 for unknown reason only for PNG files. And I don't know why.
I tried some other formats, PSD for example. Adding new commands works fine:
But exactly same commands for PNG don't show up in Windows Explorer:
I tried rename of class and commands, or use only user structure HKEY_CURRENT_USER\Software\Classes. I tried edit access rights permissions also. Nothing helps.
I suppose that there are some MIME type commands assigned to PNG format, but where I can find them in registry? Or something else?
I tried FileTypesMan and Types apps also. Some standart commands is listed, custom commands also here, but none of them work: