hi gamer, I will post my guess of the answers. 1. Unlimited people can try to be in a campaign at once, no one knows what the upper limit might be. If you use Roll20 Voice and Video, the limit will hit much sooner. If you turn off the Voice/Cam Roll20 option you could allow more. The most I have ran in a Roll20 game was around 18-23 people. I have not ever seen or heard of 100. It would be interesting to try. There is games in Roll20 with more than 100 members, but I do not know of any time that had 100 people logged in at once in the game together. Use the "Names Only" setting to minimize the amount of screen space per player. It will start to stack up into rows. At some point the rows could overflow the screen and that might be a limit, or it might stop working before that, nobody knows. 2. Making maps works great (short answer). You can insert your PNG's. It can be up to 5MB or 10MB per PNG. You can resize the PNG in the game table. As the GM role (Game creator), Put your PNG on the MAP LAYER. 3. There are multiple ways to hide things, but, doing what you asked completely you would need a Plus or Pro (paid account). With the free account you can use FOG OF WAR but when you reveal (unhide areas) it will be unhidden for every player to see. With the paid account you can use Dynamic Lighting and with the right enough settings it should be possible to hide PC's Tokens from each other until they come close enough. 4. yes, enjoy, it is legal to play games with your friends and to have 100 or more friends