Comment 1 for bug 171390

Using JPEG is strongly discouraged, because of the lossy
compression. You will lose information during conversion.
PNG export is already included, perhaps you didn't load the
appropriate plugin. GIF is also discouraged, because it is
limited to 256 colours. I recommend to export to png from
the Gxsm-menu or use the nctopng-executable or the
python-converter script, that is documented in the manual.

Possible idea for Gxsm3: Include an interface to Imagemagick.
stefan