Avatar Designs and Questions

I’ve been checking out and enjoying some of the avatars here on this site as well as a few others. I’d love to get one for myself, but I could use some pointers. As you can tell from my posts, I’m fairly new at this. In my mind, they fall into two groups: there are photographs (like those by xatm092, cdinbonds, Michelle, Slave 1, and curious_sb) and then cartoons or line drawings (used by folks like xatm092, Amy_Tenchi, Toszum, and Dark_Lizerd). They’re all lovely. I’ve decided that a drawing suits me better than a photo. I especially favor the styles of xatm092 and Amy_Tenchi.:) Here are my questions::?:

1. Where do you get them? Do they have to be created from scratch? (I’d prefer something unique to me). Since I can’t draw at all, that option is out!
2. They all look the same when displayed on the site, but I noticed most are “Small” images while some vary in size. What are the specs for these graphics? Any advice would be great. Keep it simple and patient with me—I’m getting older! It might take me a bit to get my head around everything. :wink: