1) It doesnt violate copyright, any more than sharing that information would at your local table. Roll20 is designed to be pretty robust on the copyright front: you cant share things from your campaign to someone else's campaign, so you dont need to worry about piracy. Uploading images is best as jpg, unless you need transparency then use a png. Pretty much any image editing software will do. 2) There's a feature called The Character Vault. Players can create characters in their own campaign, then export them to their character vault, and import from there into your campaign (if you';re a Pro user). It's better though to set up your own campaign, and give them character sheets and let them design their characters there. You dont need to be online, the campaign is always available. 3) If your playing multiple adventures with the same characters, its normal to just keep using the same campaign. Library assets aren't linked to a specific campaign - they are linked to your account, and you can use them in any of your campaigns. You could do it the way you suggest. If you're planning to go pro, you can use a feature called the transmogrifier to move npcs, maps, and other stuff into and out of your campaigns as needed. It;s common for people to set up a Library campaign to hold all their npcs, adventure handouts and so on, and port them into their actual played campaign as needed. If youre using mods, bought adventures, that does make things trickier. You would need to create a campaign for each of those I think, then either copy in characters via the Transmogrifier or Character Vault.