FYI, it is possible to do this by adding some parameters to the URL which brings back the image. So in the img tag, there's a long URL like this:
/QvAJAXZfc/AccessPoint.aspx?datamode=binary&name=<< app Name >>&stamp=86c8af2eb84035ac1b90fbda05618597&kind=AccessPoint
To set the height and width of the thumbnail being returned, simply add &height=<<some value>> and/or width=<<some value>>.
So, in the code for accessPoint (js/accessPoint.js) look for the imgSrc variable and add the parameters there. Also the otherImgSet variable needs to be changed to the new width also.
All that to say, none of this really helps anyway because the size of the thumbnail in the qvw is the default 192 X 108. So even with the server doing the scaling it's still going to look terrible and stretched at any size larger than that. Maybe in 12 we can get this fixed.