Upload your picture to one of the image hosting webistes, like TinyPic for example. When you upload your picture there, you'll get a direct link for it. Copy this.

Then here at MKO, in the upper left side of the screen click on Settings, then click on Change Icon. Paste the direct link from TinyPic here (in the pop-up window) and click OK.

Note: avatar pics are 75x75 px in size, so whatever you choose it'll be scaled down if it's bigger than that. Your sig+avy combination shouldn't exceed 350 KB.

Welcome!