Let's look at the modding helpfile:
Code:
6.5 #spr1 “imgfile”
The file name of the normal image for the
monster. The size of the image should be 8, 16,
32, 64 or 128 pixels wide/high. A human being
should be about 32 pixels high and there should
be 2 pixels of free space between his feet and
the bottom of the image. If the monster is to have
a shadow in the image, use the magenta color
(RGB 255, 0, 255) for shadow.
Means, unless we're speaking 'bout some old sprites taken from Dom1/2, which where 64 pixel originally, and resized for Dom3, you won't get better resolution then what is already present.
I havn't tested what happens if you use 256x256 pixel pics, but at best they get scaled down ... or they cause a nasty crash
.