The only hitch is that it requires downloading a free MicroWorlds plug-in in order to use the project. But it is a very flexible project. The project page includes a link for downloading the free plug-in, and there is an accompanying project overview page for viewing a few screenshots to get an idea of how the project works, although of course the project overview is not interactive. Basically, these are little screen shots from the project I developed. But on my project, the grid page includes a very large area for illustrating fractions.
Students can illustrate many fractions at one time.
The screenshot is pasted. Now they can print out their little GIF image and start making a notebook or bulletin board of fraction problems with unlike denominators. To assemble an illustration of a pie problem with unlike denominators, they would need to save a couple of different screenshots and then copy and paste the relevant portions into another Paint file. I really set up the project to be more of a fraction playground without worrying about saving pictures. This link takes you to the fractions project overview, and from there you can connect to the interactive project itself if you install the plug-in.