@NiLuJe Just a note, in your FAQ colour depth doesn't appear to make any difference as long as the image is formatted properly (I know your FAQ says optionally dithered down) I just wanted to confirm that the only difference full colour images makes is to the size of the file (plus it saves people messing with the images any more than they have to and thus degrading the quality), I've now tested this on my Touch, PW and PW2.
I'm also remarking on this as I've read in the past people saying that the images have to be greyscale.
Of note, if the images are full colour that doesn't mean they will display in colour, they won't as it's an e-ink display and thus only greyscale (It's the sort of thing my younger brother would ask)