highmat decoding

[JohnDoe]

I got a CD with highmat coded images from someone. It seems that it should be possible to convert from highmat to jpeg using irfan. I do not seem to understand how this can be done without yielding a horrible resolution. Is there any way this could be possible?

[Sam_Zen]

Please explain what you exactly mean with 'highmat coded images'. Can you name any file-extension ?