You are given one by default until you reach Final Stage. It is defined by your species and posting rank until then.

This is a privilege for the most active members.

Once you reach the Final Stage Ranking, you can upload an avatar this way:

• Go to your My Controls.
• Then under Personal Profile, Edit Avatar Settings

• Next upload an image from your computer or add the URL to the image.
• Finally, click the button "Update Avatar".

Note: avatars that are too large for the upload will be rejected. But you can submit them using the URL method. You can upload images at other hosting sites like Image Shack.

Be wary when uploading avatars that do not match the predefined size and shape. They will get stretched to match the forum space designed for them.