It's a bad metaphor, because if you take the image from the gallery, other people cannot enjoy it anymore, while with the right click/save you make a copy, so it's still there for everyone.
A better analogy would be if you make a painting of a painting without paying the original artist, is it stealing ?
It's not : it can be construed as counterfeiting though, and it might cause the artist to stop painting because he does not make enough money, but calling it stealing is simply wrong.
Okay, so you're one of those hung up on a definition. What do you call it when you use something without someone's explicit permission whether because you didn't ask for it first or knowingly using it after it has been posted on a website that you do not have permission to use it?
Regardless of whether it's ethical to copy whatever files in whatever situation being discussed, the term "steal" is intended to sidestep that question and make it feel unethical by drawing an equivalence between it and something most people agree is unethical.
It's a slightly underhanded rhetorical technique, so it's reasonable to put the word "steal" in quotation marks to call attention to it.
Depends on the context. If the person loses access to what I'm taking (typical in the physical world), stealing. If the person does not loses access (typical in the virtual world or with artificial scarcity items), counterfeiting.
A better analogy would be if you make a painting of a painting without paying the original artist, is it stealing ?
It's not : it can be construed as counterfeiting though, and it might cause the artist to stop painting because he does not make enough money, but calling it stealing is simply wrong.