So basically this had nothing to do with the refreshcontrol but with the image name used while init'ing the image. I used to do this:
[UIImage imageNamed:[someDictionary objectForKey:@"imageKey"]];
But what I really needed to do is this:
[UIImage imageNamed:[NSString stringWithFormat:@"%@",[someDictionary objectForKey:@"imageKey"]]];
So by turning it into an NSString, the error isn't produced anymore. Sure you need to have a @2x paired image, but even if you have those, without NSString'ing the name, you'll still get this error.