Posted: 2006-10-29T18:35:29-07:00
It's difficult to tell without seeing the files. One possibilty is that you are writing 16-bit samples (use -depth 8 to write 8-bit samples).
Use https://github.com/ImageMagick/ImageMagick/discussions instead.
https://www.imagemagick.org/discourse-server/
https://www.imagemagick.org/discourse-server/viewtopic.php?t=7692