Drawpile is a simple sketch tool which enables you to share your art with other users, and they can draw something at the same time as you. The core drawing tools are the ones you are familiar with from other design programs, and this program supports a wide range of colors to choose from. You can even add text annotations if you want to.
It supports blending modes and also layers which means that this program is much more powerful. It even works with pressure-sensitive Wacom tablets too. You can make use of this tool on your own, but it can get much more interesting when others join also, and it is straightforward for them to participate.
You can open the “Host” a session dialog and give your session a title and a password. After that, all you have to do is to click on “Host”. Other users that want to help you with your art can connect in seconds by using the password you provide them.
Drawpile handles 20 users without any problems as long as your bandwidth is up to it. The built-in text chat should help you, and the session creator can also undo some actions made by other users. He can also kick them out of the session.
When the course is finished, the completed image can be saved in different formats such as BMP, PNG, and JPG. You can even record the sketching process over time then replay it later or export as an image series or as a video.