Image dataset with timestamps?
I found a dataset with EXIF data! It's the MIRFLICKR dataset. I was looking for more amateur-style images, but this is a great start.

I'll post if I make any more findings. Other datasets that I've checked have some images with EXIF data, but they've ranged from 1 in 100 to less than 1 in 1000 images with useful EXIF data.