Not sure, but I will tell you that unless those vertical pipes are a water hammer arrester (has a piston in it or a bladder), after a short time, they end up getting the air replaced with water and are no longer effective for the most part.
You may want to check your water pressure. If you have a washing machine hookup, that is probably the easiest place to do it. You can buy a gauge for around $10 at a big box store that will screw onto the shutoffs there.
My guess is that the pressure reduction valve on the cold is shot, but that's a guess. Pipes don't normally move (bang) when you open a valve, but when you shut things off. Missing or loose straps may help. Very high pressure can do strange things, so that is why I suggested just checking the pressure. PRV's go bad, but don't blame them until you know.
Does this happen when you open any valve, or only certain ones? It could be as simple as loose washer in the valve.