Hi there,
Yes, we changed the prefixes in the Picture Corner because we found some erroneous uses of the old prefixes. It would appear that some people couldn't differentiate between ecchi and hentai, so to make matters simpler, we changed the prefixes to just SFW (safe for work) and NSFW (not safe for work).
As for the site being slow, I'm not aware of such an issue. It could be region-specific problems with CloudFlare (the content delivery service that we use). I don't know about Europe, but North America seems to be having no slowdowns at the time of writing. However, such slowdowns are often temporary and only last for a few minutes, so just try again a little while later.
Cheers.