Rendering doesn't have to mean generating bitmap pixels. In any case, the pixels you generate would get compressed before going over the wire. The HTML document

Rendering doesn't have to mean generating bitmap pixels. In any case, the pixels you generate would get compressed before going over the wire. The HTML document can be viewed as an especially convoluted vector representation of the scene (in this case, a tree) that compresses things like text very efficiently. RDP does stuff like this to more efficiently transmit window contents over the wire, AFAIK - they're not just sending bitmaps.