if you don't care about anything fancy, you can just do a rectangle background, maybe something like this.<poster id="background" color="0xffffffff" width="110" height="310"/>
<poster id="movieposter" url="myUrl" width="100" height="300" translation="[5,5]"/>
If you need something fancier you can do this by creating a "9-patch" image that gets expanded and used as your background / border. This can give you gradient/ rounded border.
aspiring