ImageMagick-Compare to a short time

i have this problem...i have to compare to .tif files and it takes a lot of time till the end of the comparing....and I need to do it in a short time. Is there a method to use for this?
i have try with "-quality 20" and it is good for some files but some other not.


Is Omeka involved in here somehow?

This is really an ImageMagick question, though, not our area of expertise.