Hmm, interesting. It should work fine but I must admit i've never tried printing on other than 8.5x11 BUT if i had to guess i'd say the problem was not with flipsuite/flipbook printer but with the virtual printer tools. I will try it out and see if i get the same results.-mouser
(Sorry - Just thought I'd chime in with a few thought)
.JPGs don't have a paginated document size. They're at the whim of whatever application is formatting them for the printer.
Print driver's (suprisingly) aren't necessarily that picky ... especially if the job sent doesn't specify a size, and the data will fit on (what's available) 8.5x11.
If liquidriver wants to print on 6x8 media, they'll most likely need to define and specify that custom size during & for the device that is actually going to put the image on paper.
Printing the image to .pdf may allow specifying a document size, but that is not going to prevent it from being overridden by the app that prints the pdf (by default) to whatever size media that is typically handy.