You may also want to check the mailing list archives. Especially Joerg and I have discussed this a number of times. GhostScript paired with an image differ would be my favourite approach.
Thanks for the tip about Ghostscript, I got it working and together with the NIST suite it have been a great help in detecting changes.
I drive ghostscript with a bash script like this:
for f in $*; do r="${f/.pdf/.png}" echo $f $r gswin32 -q -dSAFER -dBATCH -dNOPAUSE -sDEVICE=png16m \ -sOutputFile=$r $f done
and it is quite slow and cause the ghostscript console to flicker and grab the focus all the time. Annoying.
Does anyone here know of a better (and maybe faster) way of using ghostscript to convert 615 pdf files to images?
regards, finn