For the "gif" format, the image_map feature "transmit/filter all 1.0"
seems to work as expected. But for "png", "tga", and "bmp" formats such
is not the case. Is there a bug in the "transmit/filter" feature for
"png", "tga", and "bmp" or is there something I'm missing.
I'd really prefer to use a format other than "gif" that supports a
greater number of colors.
- Jerome
