If you are going to pay for the services of a photographer, do yourself a favour and use Google Image Search for photos on the photographer's website before making a decision.
There are people who call themselves photographers, who "borrow" the work of other photographers and claim it as there own. More and more the work of real photographers are illegally being used to promote the so called work of people trying to falsely lure customers in.
If you are wary of a photo, save a screenshot of it (preferably with just the photo) and use the following Google feature to try and locate the photo's origins.
If you find that the photo does not belong to the "photographer" who is claiming it does, go back to this persons site or "portfolio" and take a screenshot again. Make certain you get the date and time on your computer in the screenshot as well.
Do also check for comments regarding the "photographer" as there are fraudulent companies who issue threats to anyone and everyone if anyone takes them on. These people invade your privacy claiming they know all your personal details and can very well threaten your life and commit fraud with what they claim to have.
If this should ever happen to you, report it to the police for your own safety and keep a record of everything.
If you can't find information on a photographer, communicate with an online photography community and query as to whether or not the company is legit. Photographic communities provide a huge database of knowledgeable members who will most likely have come across the person you want to hire.
Protect yourself, a cheap photographer is usually a crap photographer. No offense to those just starting out but the reality is that there are too many so called photographers popping up without any knowledge of what they are doing.
There is more work that goes into photographing an event than you realise. Hours and days of work with hundreds and maybe even thousands of photos. Check prices, be careful of low rates because you can't redo your wedding, or your 21st birthday and so on.
I know of a few so called photographers who have been reported. If you suspect someone, gather as much info as possible.
Criminals create a gate way to hell for photographers. You have been warned.
Update: website of interest for finding information: www.waybackmachine.org.