You'll need:
 
- The perl module Perl-Imager. You need an already installed
   libungif port. Please make sure gif pictures are really enabled.

- Perl module Image::ExifTool and a patch for GIF pics:
   http://antispam.imp.ch/patches/patch-GIF-Colortable

- Perl module String::Approx

- Gocr from http://jocr.sourceforge.net and a patch to
   avoid segfaults with gocr:
   http://antispam.imp.ch/patches/patch-gocr-segfault

- Netpbm from http://netpbm.sourceforge.net
 
- Libungif for fixgif and animated gif support.

Check if you have the necessary tools like giftopnm,jpegtopnm
pngtopnm, djpeg, pnminvert all in the same path.