Hello RoKos - thanks for using the Slingbox Answers Forum!
Sorry to hear you're having trouble with the video size using Internet Explorer and Watch On Slingbox.com. Here's a link to a troubleshooting article that details how to reset IE:
If this doesn't help, please let us know. The more details and information you can provide, the better we (the forum community and Sling Media) can help.
The Slingbox Answers Forum Moderation Team