Hm, a bit puzzled here
I posted in the Calibre Editor section, thinking it applies to changing covers during an edit session. I really wouldn't want to add an image to the book (say, PNG) and have Calibre automatically convert it to JPG. That's not the case with the new feature, right?
And what does it mean "to store image file types as ebooks"?
@eschwartz
How do I run the command? I'm using Calibre Portable, BTW.