Hey Bearpaw,
Typically with infrared pictures the picture is taken with lower megapixels than when the daytime pictures are taken. If you read into it you'll usually see something like 5MP daytime / 2.0 MP nighttime. I really haven't noticed a huge drop off in quality though.
Another thing though, a flash camera will almost always have more range at night than an infrared. What you look for with an infrared camera is the amount of IR emitters. The more emitters the more infrared light the camera takes in, meaning the further out it can reach and the clearer the pictures will be. Again, I personally think the extended battery life with an infrared and the much smaller chance of spooking the animal outweighs the flash cameras. Do a google search or look at the major camera companies photo galleries to see the difference between flash and IR.
And yes, you can get IR cameras that are higher megapixels, but you'll have to pay more. I just saw this bad boy on the Stealth Cam website. . . Huge video, full audio, 8MP, up to 16MB memory card!
http://www.stealthcam.net/HTML/sc_prowler_hd.htmlHope it helps,
Alan K