[Magick-bugs] Crop produces small and corrupt files when working on really large files

[Nick Burch]

Hi All

I've found an problem when cropping really large pngs.

I start off with a 14mb, 14468x13523 png. I run it through
 	convert -crop 14464x13504+0+0 Pre-Crop.png Post-Crop.png
and I get a 2.4mb png which is mostly black, with the odd band of picture.


I've found this with imagemagick 6.0.6 and 6.2.4, both on i386 Linux

The images are available at:
 	http://gagravarr.org/misc/Post-Crop.png
 	http://gagravarr.org/misc/Pre-Crop.png

Thanks
Nick