x.jpg could lead to x.jpg/index.html, if I'm not mistaken.
I will confirm that the commands to copy and paste are the same in Linux as windows. However I have seen people having trouble with pasting in the chat text box. I have come to save them.
I have recently been having problems pasting in the chat with the ctrl+v command I would paste and nothing would happen. I later found that there was a program that was inhibiting the command and that program was the mouse locate program. You know the one you press ctrl button and your mouse location would light up with a ring to help you find it on the screen.
As soon as I disabled mine I was able to paste into the chat window again.
I had a little trouble with this too, to copy and paste in Minecraft you use Ctrl+A to highlight the text in chat and use Ctrl+C to copy it and Ctrl+V to paste, if it's outside Minecraft, you just use Ctrl+C to copy it then use Ctrl+V while in Minecraft to paste it. Hope it helped
P.S. This method only works on Windows
Actually, the method works on Mac. It's just that you need to use the command key instead of the control key.