
Public room info. cards only show the top 332x147 of your total image. For featured rooms, they show the full 332x281 image. Also note that on featured rooms they have a hazed out bar at the bottom, starting at 218, where the room name and owners name appear along with the rooms rating. I have included the room rating stars, as well as user count in case someone wishes to shade those areas in their final images. (side note, when receiving an invite to a public room, the full image will show to the person who receives the invite.)
I know as IMVU changes, things like this can change as well. If you find my dimensions are off at all, please let me know and I will be sure to fix it.