temp files left behind
ImageMagick creates temporary files on occasion. It will remove them if the process completes or if the Windows OS sends a signal that can be caught. If the process is killed, for example, some temporary files may not get removed. Under these circumstances thet must be removed manually or by script. All ImageMagick temporary files begin with the prefix magick.
Open source is all about contributions from the user community. Feel free to fix the ImageMagick signal handler so it properly removes the temporary files under Windows when a ctrl-C is pressed (note this works fine under any OS but Windows). Post your patches here and we will get them into the main ImageMagick source distrubution.