I cannot fathom why you would want to do something like this.
the easiest way to do something like this would be to go to Admin panel -> Manage -> Forms -> Ticket Details.
Click on the Issue Details config button.
And enter it in the Help Text.
I don't know if you can do images this way, but you might be able to.
I also think that it would disappear when the person starts typing.
I do not know how to achieve this otherwise.
