I ran into a similar problem where I wanted to place a static image legend on an OpenLayers map. My solution was to use the attribution element http://dev.openlayers.org/examples/attribution.html (look at the source of the page).
You can change the attribution of the image instead of text:
'attribution': "<img src='myimage.jpg'/>"
As for changing the position of attribution on the map, you can change the css properties for div.olControlAttribution, for example.
div.olControlAttribution { left:10em; top:10em; }
quarkdown27
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