for sure- a couple seconds saved per sample will amount to many hours of saved time even for a small dataset.
I created an issue to track interest in keyboard shortcuts, but I've heard this feedback from the friends I had beta-test so I think it's gotta be next on the agenda :)
You can load tens of thousands of images into the web app at a time. Unfortunately after 100,000 I start to see performance issues- especially with collaboration.
I'd like to fix this in the future- but with a web application these limits are hard to break through.
Yes, that should definitely be fixable. I have a simple Flask image labeling app (whole images, not items within them like this), and it has no upper limit. Millions is just as quick and easy as dozens. It's so primitive I don't even use a DB, just one flat file per 10,000 images, that can then easily be processed with grep etc.