Breaking the Gallery
Added just one 600x600px image.
Each subsequent edit added one extra image
Added files 2, 2.1, 2.2
Added files 2.1, 2.4, 2.5
GLITCH: thumbnail did not scroll to image 2.5 when it should have (although it did highlight it properly, confirmed by manually scrolling)
Added file 3 (1920x1080px)