upload jpg > image not accepted - solution: cmyk > rgb

[swisswuff]

following problem occured:

tried uploading a jpg resulting from a very nice quality image obtained using a xerox photocopier/scanner a while back.

this upload attempt did not work on otherwise perfectly functioning coppermine 1.2 final release standalone installation using gd 1.x (host specified, no determinations by me).

my observation was that these images that would not work were saved in the format of CMYK-images in jpg format, instead of RGB-images. adobe photoshop makes a distinction, whereas graphic-converter (mac os x) does not offer both modes, only rgb.

neither coppermine nor gd documentation seem to highlight that this format difference among jpg-images can lead to problems and i could not find the keyword CMYK on this forum so maybe this is an unimportant issue.

*my* problem was fixed by saving the jpg-images as 'rgb' jpg images instead of their previous 'cmyk' jpg format. what i do not know and can not test is whether new versions of gd would effectively deal with CMYK images. according to the sf.net website, imagemagick offers cmyk image support. (http://imagemagick.sourceforge.net/www/api/types/Image.html).

wolf schweitzer.

[Casper]

My server runs GD2, so I tested this out.  I changed an image(known to be good and already uploaded in rgb) to CMYK, and tried to upload.

It failed, as 'image corrupt or type not supported'.  

[Joachim Müller]

afaik GD only supports RBG true color.

GauGau