Personally I don't mind them; your pic isn't clear but they are probably either pond snails or ramshorn snails, which only eat plants if the plant is dying. They do reproduce very quickly but if you don't overfeed your fish they shouldn't overpopulate, but I guess your view on this depends on how many snails you would consider too many.
Frankly they are so hard to avoid that I find it better to just relax and go with it. They don't hurt anything. Even if you dispose of the visible snails, it's very likely that there will be eggs somewhere. Some people find it worth it to keep disposing of them, because they are really bothered by snails in their tank. Me, I just live and let live. ? It's up to you.
