CImg: jpeg export fix * alpha channel is dropped when exporting 2 or 4 channel images to jpeg * Reason: CImg interprets a 4 channel jpeg image always as CMYK
CImg: jpeg export fix
* alpha channel is dropped when exporting 2 or 4 channel images to jpeg
* Reason: CImg interprets a 4 channel jpeg image always as CMYK

Sparkier/inviwo,inviwo/inviwo,Sparkier/inviwo,inviwo/inviwo,Sparkier/inviwo,inviwo/inviwo,inviwo/inviwo,inviwo/inviwo,Sparkier/inviwo,inviwo/inviwo,Sparkier/inviwo