You can take photos, so long as you get permission, BUT, I believe, just my humble opinion, that if you do, and you want to post it online to be shared by thousands, they need to be told so that they know it is not for personal viewing. Internet ettiquette I would assume. I don't mind too much if sb takes a photo of me, but if I see it online, I would be furious. How you ask about posting online, I have no fucking idea (maybe that's where a tip comes in to compensate for the right to publish - G-A-R-Y can probably tell you about that since he appears to be the king of photo-taking on this forum, so maybe a gift of the gab???), but I have heard horror stories of pimps taking it out on girls who have done this (verbally or financially), due to the cost of photoshopping etc. and the potential loss of earnings due to a less than appealing "deer in the headlights" candid shot. Candid shots catch them in their rawness, which also makes them easier to be recognised on the street - photoshopping can give them some anonymity (though probably mainly psychological). Some girls work independently and most would know that digital photos easily find their way online, but it is still better to ask. Just my 2 cents.