3.) DON'T CROP OUT THEIR WATERMARKS! When you see a pic of yourself from a show on a photographer's Facebook, first of all, it is best to ask permission of course, but the LEAST you can do is leave the photographer's logo/name watermark (that's the little logo/wording in the corner) on the photo. If you can't leave the mark in the photo when you crop, DEFINITELY take a few seconds to give credit to the photographer in your photo description (tagging/linking their photography page is even better!).
4.) Always Give the Photographer Credit. Whether you paid, gave a free comp ticket, or blatantly stole a photographer's photo, you should always give them credit wherever you use the image, unless you have a written agreement that says you can do otherwise. Photographers own the copyrights to the images that they take with those cameras, and using their photos without permission is illegal… and they can sue you. Most of them won't sue you unless you're a giant douche-canoe to them, but they can. Many (but NOT all) of them will also forgive your unauthorized, not-for-profit uses of their images (like making a profile pic out of them) if you give them credit… but that doesn't stop it from being illegal, and you should still offer to pay them for your use of the photo.
5.) Give the New Guys a Chance. Even if a budding or hobbyist photographer's work is not super-mega-fabulous, still give them a shot (see what I did there?) at photographing your band. Making friends with new photographers can be an investment. For instance, we had a couple friends back in 2008 and 2009 who would come out and take pictures at tattermask's shows. They were hobbyists, and their photos were effective documentation of the awesomeness of the shows they came to, and there were some great shots here and there, but still not professional grade work. YET. Fast forward to 5 years later: those guys both own professional photo companies like Altered Ego Images and Gene Lazo Photography, both boasting FANTASTIC portfolios of live music photos (and other great shots, too!). We kind of grew together, and now we have a great mutual appreciation and friendship, and these guys come to our shows often (and we get them on our guest list) and they take great pictures that we're excited to share all over social media!