gtk_image_set_from_file forcing pixel depth

[Kent Schumacher <kent structural-wood com>]

I have an application that allows the user to look at a large
number of sequential jpeg images as a movie.

It does this by simply creating a gtk_image and then looping
through gtk_image_set_from_file for each sequential jpeg
image file name.

This works wonderfully quickly when running at 24 and 32 bit
depths at the computer and at 8 bit depths at an X-terminal.

Unfortunately, it slows down enormously at 24 and 32 bit depths
when used on an X-Terminal.  This is unfortunate because the X-terminal
is where the application is going to be used.

The question is, is there any way to force the gtk_image to display
in 8 bit mode on a 24 bit X-display.

If not, is there any way to speed up the display of the jpegs? (note
I want to keep the jpegs stored at full bit depth, and keeping them stored
in both 8 and 24 bit depths is prohibitive - we are talking about
hundreds of thousands of photos).

Thanks,
Kent