You probably figured this out by now after turning on the TV/DVR that you Slingbox is connected to and seeing it, too, had a tiny little picture.
I turned on my TV after working with this problem and, low and behold, I had the same tiny picture.
What I think happened is I clicked the Guide button on my remote while using the remote in a Slingbox session. It brings up the guide and puts the video into a little box until you exit the guide, or at least that is what is supposed to happen. When I exited the guide in my Slingbox session on my computer, the picture stayed tiny. I thought this was a viewing problem only in Slingbox sessions, and I worked hard to correct it, but to no avail. Then I turned on the TV, like one would on any TV that a Slingbox is not connected,, and discovered it actually was a real viewing problem, which probably was caused by using the remote in the Slingbox session.
All I had to do was push the Guide button on my real remote, and then push the Exit button. The display returned to normal.
1. I was using a Windows 7 64-bit computer, SP1.
2. I was using Internet Explorer 8.
3. I was using the latest Slingbox plug-in for Internet Explorer 8, version 220.127.116.11.