This won't solve your problem, but seeing that you're new to MED I just wanted to sneak in some advice... Hope you don't mind.

When it comes to optimizing a game, it will also include the amount of memory the model takes, including the skin.

Now granted, if someone makes a whole level out of models with only 256 x 256 skins, it'll be pretty optimized to begin with.

But what I'd like to point out is these things:

BMP files are HUGE and with no better quality than .PCX
Use PCX over Bitmaps for skins.

However...

24 bit TGA files are better quality than PCX, and still smaller than BMP files.

An example of the quality differences is especially visible with gradients.

If you had a skin that faded from black to white for instance... the greyscale color changes wouldnt be smooth. They appear as noticable bands.

With a TGA file for the skin, gradients are a smooth transition.

Anyway, I would just get in the practice of using TGA or PCX files for everything since BMP files are so big and will really add up in the end.

- Jason