I have no way of knowing if anyone is working on posting contributed pictures if they don't leave a message. For pictures that require downloading to our local PCs for edit and resizing I don't want to start on a movie if someone else has already downloaded them and started to edit. For some pictures this takes a lot to time.

Would it be possible to put a box at the top of a contributions topic for us to indicate when we start on working on them?

You can mention it in the topic (i.e. post a reply), then other member that would read the topic would see your reply at the end. The same way, before processing pictures of a topic you would have to read first all messages to see if somebody will process it.
I'll continue to do the image uploads of Rinspeed's topic; as these are usually European cars for French shows, it is easier for me than for you I guess
Now we just have to contact wickey or hope that he reads this topic...

OK, with just you wickey and I there should be no problem. I will post a message when I start to work on a movie.