What's wrong with my icons?

I decided to make some icons, following the directions in the FAQ on this website. Some of them were hand-drawn in Paint, some were a combination of cropping small parts and scaling down clipart from one of the free clipart sites with some modifications (it's extremely hard to recognize any of them from the original picture, so I doubt I've violated any user agreement since they are almost more inspirational than anything by the time they get to 24x24).

So, I uploaded them with my POI. And the icons that were in the POI Icon library loaded fine, but the icons I made turned out blurry and I'm not sure why. All are <24x24 and 256color BMP. Any ideas? One or two of them turned out nice and might be worthy to upload.

I have a Nuvi 350 and like I said, the other icons from the icon library worked fine.

-=Eric