I think it depends. Generally, I think slingbacks are meant to be worn with bare legs or maybe with stockings, but I think they can work with tights if it's done in a deliberate way. I actually like the second picture for that reason. I don't think you should do it if your only reason is you're cold and you're not sure if it's OK or not.
Get used to me. Black, confident, cocky; my name, not yours; my religion, not yours; my goals, my own; get used to me. -Muhammad Ali