IMHO....this is not difficult if you know what you are doing and have done it before. If you don't and haven't, let a more knowledgable/experienced person do it.

Same opinion about electrical work: doing it right isn't rocket science but the consequences of doing wrong can be dangerous and expensive.

Some local codes may require a licensed professional installer to connect gas appliances ... but that's not to say you can't do it if you're comfortable and able, and there's no inspector involved.

Did you take the pic with an iPhone? Those often are oriented horizontal in message board postings even when they were taken vertical.

That's a rather weird position for the gas line to come in the wall. Usually they are down near the floor. Did you have the gas line installed when your drier was installed vertically stacked?

You can do this yourself, but you have to be dead sure the gas turns off at the valve. Also use a gas pipe tape on the connection threads. When you are done, turn the gas on and then put some very soapy water on the new connection you made. No bubbles? Then you did it right. Bubbles, check it again, you have a leak.