Flickr

Anyone know if flickr allow 'adult' pics

Can't say I've seen any on there
They do allow for a fair amount of artistic expression so you will find some glamour/nudes but I wouldn't expect pornographic material to be a regular find. You can make images private as well, that however would stop you linking them outside Flickr

More to the point what are you thinking of putting on there? You might be able to host your own images on there but Flickr isn't some small time image host that will ignore copyright infringement so if you do have adult images you'd best make sure you own the copyright or have a license to use them

Was just thinking of putting some caps on there, but after using it and realising what a pain it is doubt I'll use it again

That's because, along with deviantart, it's aimed more at people who create images, file them, tag metadata and descriptions and such rather than quick disposable stuff