Can anyone tell me how to upload a photo to my avatar?

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I had joined mylot for about 1 year ago. but at that time i had not uploaded my photo in the avatar. But now if i upload the photo it goes to my album, but does not get upladed in the avatar, it is still in the default photo. can anyone tell me how to uplad the photo in the avatar. i.e.. the photo above my user name. can anyone help me in this? waiting for the responses.