"There is so much mystique about this with new RE photographers, it seems that most of them think this is some sort of natural phenomenon that hasn't been figured out by science yet, or something. Few understand that these are websites that are administered by humans."
Why do you need to understand your MLS?
Because MLSs are a services/associations that your clients belong to that regulate and control how text and photos about properties for sale are distributed. MLSs control all of the rules used to carry out real estate transactions in a given area. As a photographer the most important part of the MLS rules you need to understand is rules regarding photos like to finding out what the technical specs for photos are, and the rules regarding watermarks, branding, For Sale signs, and whether the first photo has to be an exterior, etc.
How to find your local MLS website?
The first step is to find the website of your local MLS. The reason you want to do that is that the MLS website will have contact information that will allow you call them up and ask questions. Some MLS sites will have some photo rules that you can just search through and find what you need but most don't so you have to call them and ask. I'm in the process of making a US MLS directory that has a link to most or all MLSs in the US but I just started today and it has a ways to go to be complete. So below are some instructions to find the MLS that your clients belong to:
Call up your MLS and ask for their rules concerning photos
Call up the MLS, tell them you are a real estate photographer and ask them to email you their rules for photos. The thing you want to know is what should the photo dimensions be, what is the maximum file size, what are their rules for branding, virtual tours, the first photo of the listing etc.
Stay cool - don't flip out when you find that rules are totally insane
Many MLSs say that the act of uploading photos to their MLS transfers the copyright to the MLS. As we've talked about many times before this is not true according to Joel Rothman an IP lawyer... you don't need to personally fix this problem and alienate customers in the process, just understand their point of view. This problem will eventually fix itself. Some of these MLSs like WVMLS here in Salem have been operating since the 1940's and haven't changed much since then.
In any given location your clients may be members of more than one MLS
Where I live in Salem, Oregon there are two MLSs WVMLS and RMLS and some agents belong to both and others belong to just one. This is true in other locations too. Don't ask me to explain it. It's just the way it is! Most MLSs will have a map some place on the site that explains what counties they serve.
As I said above, I'm working on a MLS directory but it is far from complete. If you have info on your MLS that I don't have in the directory please leave a comment on this post or on the mls-directory page and I'll add it to the directory. Collectively we can build a pretty good directory.