Did someone try this : In FuzzyOCR config file/etc/spamassassin/FuzzyOcr.cf, replace #focr_bin_gifinter /usr/bin/gifinter with : focr_bin_gifinter /usr/bin/convert -interlace as stated here : http://spamassassin.1065346.n5.nabble.com/Image-spam-FuzzyOCR-tp122418p122427.html
Here is the answer : https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=808572