Most art galleries carry insurance on the pieces they hang or have in inventory, usually against theft or fire. However, that doesn't mean that ALL art galleries carry such insurance.
Basically you should know the features of your camera for you to know how to take the shot. Better to read the manual first. But when it comes to photo shoot techniques and other photo enhancing...
It depends on the gallery... Some galleries have studio space attached and, given the artists permission, may be used as gallery space for that artist as well. People like seeing into the "behind the...