I accidentally tried pasting text with images from a word file into the WordPress editor - it only pasted the text, as I expected. so I went to upload media the normal way, and suddenly I can't upload or even view my media.
Also, above the "Dashboard" sidebar button, but below the WordPress logo and my site title, a bar of horizontal whitespace has appeared. As these happened at the same time, I'd assume there's a link?
whatever has broken this has also broken the 3D slider on my front page, but seemingly not any of the other sliders.
EDIT - Solved: My Sitemap generator was interfering for whatever reason.