Looking at Ambrosia Publishing, the OP is pretty much a cut-n-paste from their front page. I went rummaging for the answer to "what ebook format is ebook?" but couldn't find anything, so by investing a dollar, I bought a novel in ebook format.
The download is a zip of a PDF file. Hmmm. I think they are missing the point here...
Especially as the PDF page size is 10.42x15.86 inches, with 1"-1.5" borders on all four sides. At least the majority is in monochrome.
Is there a good, reflowable, e-format for graphic novels that we should recommend to them? Mobipocket perhaps?