All free imagehosts have ads and pop-ups. That's their daily bread.....
Using good pop-up stoppers takes care of it.
Risk of spyware exists with all sites incl. imagepile. Here again using an efficient (regularly updated) A.V. takes care of that as well.
If you click a link (eg. in some forums) with many hosted pic-links, it helps if you clear your cache for quicker downloading.