Someone is actively trying to hack into your account. I suggest restarting your computer, searching for any viruses and repairing the launcher. You then need to change your IP adress. If you get asked during logg in to enter a code that you got sent over mail, the hack worked and once you check your bank you will notice that 1k gold is missing
That's someone else's addon. You can change the Ready check messages. As for the image, it IS an ingame image, one of the many assets available, which is why you can see it.
You can sometimes see some people using it in guild notes, see that example for instance:
Another example:
Example of guild note:
|t150:150:esoui\art\icons\mh_second_wolf.dds|t