The megapixel settings will not make a difference in the shots for auto claims purposes. For the most part it's all about lighting and choosing the right setting on the camera for the shot you need... macro is the most commonly overlooked setting for those close-up shots.
I use a Fuji camera 5.0 pixel, but I never take the quality setting above 3 pixels for storage and upload space. The software has photo limitations so the lower the resolution the more I can attach to the file.
One thing I have noticed is that you need to clean your lens every week with the proper kit. There was a great article on the internet about using digital cameras in auto claims. I'll see if I can find it.
Megapixels probably isn’t the problem. I’ve taken wonderful, clear pictures with a camera capable of only 1.3 megapixels. Here are a few suggestions for improving your photos:
• As others indicated, clean your lens. Don’t use a shop towel, get a lens cloth. You can get a cleaning kit with everything you need for about $10. If the lens is really dirty, use a lens brush then put a little water on the lens cloth and gently clean the lens.
• Were the settings on your camera changed by a user? Modern digital cameras have an abundance of settings and if they are incorrect, the photos suffer. The Book of Forbidden Verses (owner’s manual) will tell you how to reset the camera to factory defaults.
• Lighting makes a big difference. I used to take photos in a poorly lit drive area. No lights near the cars. The photos were awful, and while the flash helped, it caused glare. Position lights over the area where you take photos.
• If you have to use the flash, but your photos have a lot of glare, a diffuser will help. You can make a diffuser for point-and-shoot cameras out of a plastic milk jug.
• If you find it difficult to hold still, get a monopod. They start at $25. They are easy to use, much faster to setup and take down than a tripod.
• If you have trouble getting close-up photos of the damage, this might be a reason to buy a new camera. Some cameras take better close-ups than others. Make sure you know how to use the close-up feature of your current camera before you buy another camera.
• Most cameras aren’t built to withstand the fine dust that bodyshops generate. Lenses that extend and retract can pull dust into the internal mechanisms. Dust degrades photo quality. Keep your camera clean and put it in a clean place when not in use.