Been slow, but have waited it out as I have something like 8000+ pics on my account.
For the pop-ups? Never see them. Firefox w/ ad block.
Like you I have a lot of photos already there or I would have given up a long time ago. I use Firefox & ad block too; still get 2-3 pop-ups every time I get on the site. I'd tell you what they are if I could get on! Today it mostly times out or I get an "unexpected error" screen.
Later: whaddaya know; I got on! First a scrolling ad square in the lower right hand corner; then a full page of "sponsored ads" with the heading "continue to site"; then a couple of scrolling ad squares among my photos - an $11 large sausage Casey's pizza, something called Creative Cloud, and Columbia sportswear from Dicks Sporting goods among others.