My advice, in either situation, would be to at least politely let the provider know what the discrepancy is between her advertisement and her appearance. It may encourage her to take a second look at her marketing and make her aware of the perceptible changes she maybe didn't notice.  

It is certainly fair to expect a provider to have up-to-date photos that represent her current physical appearance. While minor changes like hair color, hair length, piercings, and tattoos may not warrant a new set of photos- in my opinion those things should be noted by the provider.  

I can't provide much feedback on the DNS list. What I will say is that there are providers who DNS clients for many things. I have sometimes received notices from certain other providers cautioning against seeing a client for superficial issues. This type of issue is something I would overlook, provided the client's reasoning for pointing out the discrepancies was sound and that it was not a pattern that demonstrates that he/she was using it as  a technique to effectively waste people's time.

but sometimes the little head will override the big head.  You may get blacklisted, but it is the chance you take.  I for one, would rather walk away then not get what I had expected , but that is just me.  Truth in advertising

In any case, it's a bit of a tough call but if you really think the ad was misleading you can walk. Bear in mind though that you really should not take the pictures to be perfect representations -- for lots of reasons so should set you own expectations accordingly. 20 pounds and 10 years may not really matter. Lots of mid-30s and even early 40s women are very attractive, reasonably fit but will be fuller than the 20 yo you were hoping for. Now, if you get there and the 20 pound is a beer gut and potbellies are not your thing....

In other words, if you  are not being a complete ass and overly critical you probably don't need to worry about getting BLed for walking away. If you start doing that a lot and particularly with providers that are reasonable looking and have fair reviews for your research, yeah they will likely spread the word.

That gets to the last point -- what's your research process? Look at hot pics and say "ooooh I want that one, sooooo pretty." as the drool runs down you chin. If so do more work and your results will improve.

Sometimes it's not what you say but how.  
If her pics are misleading she already knew that before you even showed up imo.  
So...she can't really be too mad at anyone else but herself.

PM I can give you some valuble info.

Politely, walk away.  Inaccurate pictures are a misrepresentation that unfortunately does not affect only that particular provider but to the whole pool of providers in this site and any other.

xoxo

I feel that you definitely have the right to politely decline and leave. At the end of the day you are paying for a service, if it is not as advertised you have no obligation to go along with it. I do recommend that you let her know your reasoning and it may help with not getting blacklisted, but like another girl said above girls blacklist guys for a number of reason, some IMO very stupid reasons. But all in all it is considered false advertising. You don't see an ad for a shirt then go to the store and buy it and it is completely different than the photos.