I'm providing 3 demo accounts for a farm that i'm creating right now.
You will be able to upload files and render on the farm without any limits in the next 30 days (at least). There aren't so many nodes but more could be started up if needed for the test.
The farm has a web interface and also a sync program, so you could sync a local folder onto the farm (obtaining real time images from the farm).
I must say that the upload speed on the farm is not so great due to the budget for the farm, but depending on the tests and the response, could be improved.