I went deeper in the references bug posts and I found the answer in bug # 10112! I had to add: (add-to-list 'image-type-header-regexps '("\\`\377\330" . imagemagick)) But just for my knowledge, what is "\\`\377\330" ? -- Kaushal Modi On Wed, Oct 22, 2014 at 2:45 PM, Kaushal wrote: > Thanks for your reply. > > I evaluated (setq image-type-header-regexps nil) and verified that it is > actually set to nil by doing C-h v on that variable. > > But (eq image-type 'imagemagick) is still returning nil and I am M-: > (image-transform-set-scale 0.1) still does nothing. > > > > > -- > Kaushal Modi > > On Wed, Oct 22, 2014 at 1:52 PM, Glenn Morris wrote: > >> >> This message was over 1 MB. Please compress attachments in future. >> No need to resend this one, since interested people can fetch the >> attachment >> from http://debbugs.gnu.org/cgi/bugreport.cgi?bug=18797#5 . >> (But I think it has no relevance anyway.) >> >> Kaushal wrote: >> >> > I have compiled emacs with Imagemagick (the config.log file is >> attached). >> > >> > But "M-x image-transform-set-scale" is not working for me. The image >> scale >> > stays the same when I set the scale to 0.5. I tested it with bot png and >> > jpg images. >> > >> > But the eimp package is working fine (which uses mogrify from >> Imagemagick). >> > >> > When an image is open in a buffer, evaluating "(eq image-type >> > 'imagemagick)" returns "nil". >> >> Right, so it's not an ImageMagick image, so you can't transform it. >> Emacs uses libjpeg for jpgs by default. >> Try testing it on a format that Emacs does't support otherwise, eg bmp. >> You have to force the images to be created with type imagemagick to be >> able to scale them. This remains poorly documented IMO; >> http://debbugs.gnu.org/10746 >> >> > What am I missing in enabling the imagemagick detection for functions >> like >> > image-transform-set-scale? >> > >