If you are using Lindner-TeX and you want to include a GEM image into your DVI file you have to add !tex_lindner to your preamble.
UDO replaces the tool called IMGTOTEX that is part of Lindner-TeX. UDO has all functions of this tool built in.
To set the size of an image you have to use the !tex_dpi command.
Example:
UDO reads in the header of tiger.img, calculates its size and adjusts the header to 100 dpi. In the destination file a TeX macro will be generated that includes this image and displays it with 100 dpi.
Hint:
Using 100 dpi screenshots are displayed in the original screen size on my HP DeskJet 510. !tex_dpi can be used before any image. If you are using an image more than once you shouldn't try to display it in different resolutions. Use a copy of your image instead and display the original one with the first and the copy with the second resolution.