Go ahead and dress your "character". Hopefully you have found some clothes, hair and perhaps a prop that will suit what you want them to look like. If you're at a loss, peek in my blog for some links to free stuff as well as in the freeby sections at some of the brokerages like Renderosity and 3dcommune. Don't forget to look for skin textures so that the character looks more realistic- if that is what you're going for. We have a couple of sets of free lights here in our own download section as well. I'm using set one from our Sexy Shader lights. You may want to add a background of some sort or put other things behind the character to give the image more of a "story". The creative part is all up to you!
Rendering to size can be valuable in a number of circumstances. In this case we need a very small render size. To change the render settings go to Render in the tabs along the top and choose render settings from the drop down selection. You should then see something similar to the image below pop up on your screen. The changes will be made in 'Dimensions'.
Choose the custom preset and the pixel dimensions that you need for the avatar. In this case my avatar needed to be 100 by 130. Another option is to render slightly larger than you need and then crop for size in a 2d graphics program.
Once you have changed the render size go ahead and do a test render. Because it's so small it should render quickly. You may choose to make changes in the camera and focal settings again at this point to get just the perfect shot.
This is a very simple avatar rendered at 100 by 130 with the cameras settings at 150 for the Z translation and 93 as the camera's focal length.
Save your render and your done! One final factor you may need to check on is the file size for the site you want to use your avatar on. If it is to large you may need to compress the file slightly with a 2d graphics program before posting it.
