How to transfer graphic to phone???

I have an lg vx-4500. It has several built-in options for screen
background images. But I'm sure there are ways to download new ones. I
haven't looked into this at all. Is "get-it-now" the mechanism to use to
view/download images? And what methods are possible to download custom
images? If I took a picture of my car, for example, and wanted it to be
the background screen on the phone...how do I size the elenctronic file
and how would I transfer it to the phone? Again, I haven't yet begun to
investigate this, and I'd appreciate any advice from those who already
know...

Thanks...

- Dave