Post any defects you find in the released or beta versions of the ImageMagick software here. Include the ImageMagick version, OS, and any command-line required to reproduce the problem. Got a patch for a bug? Post it here.
Several images are successively displayed in the root window, then
I get a blank image. Using 576x384+0+0 (i.e. adding a location)
solves the problem here (unfortunately the documentation is missing).
Crop repeats if no specific x,y offset is specified. See http://www.imagemagick.org/Usage/crop/#crop for details. The solution is to specify the offset as the user suggested:
We can reproduce the problem you posted and have a patch in ImageMagick 6.4.0-8 Beta to fix it. 6.4.0-8 Beta will be available sometime tomorrow. Thanks.