add the following code into your html

{block:ContentSource} <!— {SourceURL}{block:SourceLogo}<img src=”{BlackLogoURL}” width=”{LogoWidth}” height=”{LogoHeight}” alt=”{SourceTitle}” /> {/block:SourceLogo} {block:NoSourceLogo}{SourceLink}{/block:NoSourceLogo} —> {/block:ContentSource}

(Source: milkxothemes)

upload the picture to tiny pic or whatever and copy the direct link, then go to the html and where it says

<div id=”menu” style=”position: fixed;”>
<center><a href=”/”><img src=”{PortraitURL-128}”></a><p>
replace the {PortraitURL-128} with the link to your picture