I saw that mirc cannot open that link "https://mircscripts.net/snippets/project[RtX3K].jpg" that is valid, not even changing the mouse cursor as pointer when moving up on it.
That is not a valid URL. It may work, but the official standard requires that those square brackets be encoded (as %5B and %5D) instead. As you can see, this forum also does not recognize your full URL as valid.