I think Phatch is a great and wonderful app.
It is easy to use, powerful and, of course, free and opensource.
You can use Phatch to convert and edit easily a lot of pics and there are no any similar portable app.
So, please, could you add Phatch as a portable executable?.
Here, more info:
I don't do a lot of image work but
Irfanview (available as a PA) at least does batch processing
and the set of progs under
https://portableapps.com/apps/graphics_pictures
seems to cover most bases so I'm wondering what is unique ?
Wm