Add image counter/image limit

[Etheriss]

I saw in another issue that you're working on the new version and I'm very happy to hear it, love using your app!

If possible, I'd also like to request a feature: could you please add an image counter and/or image limit to the sessions, for those of us who like to keep track of the number of drawings we've done?

Of course I can keep track manually, but I think it would be nice to have it as a part of the app, considering the time-limited nature of gesture drawing.