I would check the progressive setting first. From the cjpeg man page:
"...progressive JPEG is not yet widely implemented, so many decoders will
be unable to view a progressive JPEG file at all."
For those not familiar with it, a progressive jpeg, the picture is stored
in multiple scans of increasing quality. This allows the picture to be
more quickly displayed over a slow link, although with low quality. As
more of the picture is downloaded, the quality improves.
If you want to remove the progressive, and don't have access to the
original file, on *nix machines, a program called jpegtran is available
(part of the libjpeg-progs-6b package). Supposedly it can change the jpeg
type (make a progressive non-progressive) in a lossless manner, along with
a few other modifications.
> I have an epson stylus photo 915 printer which can print pictures from a
> cf card. I succesfully wrote an image in jpeg from gimp to the card and
> could print it after having inserted the card into the printer. However,
> today I saved another image, and the printer didn't recognize the jpeg.
> When I put the cf card into my camera it read 'incompatible jpeg type'.
> Does gimp save it's jpegs in different 'types'? I couln't figure out if
> there are any settings to do this...