How do I set the height to a tableFooterView loaded from a xib

I'm sorry for the confusion, here's the updated answer:

I know you can do this by setting the frame height, but it might also work with auto layout just by re-assigning the footer view after your imageView has finished loading.

// either let auto layout calculate the frame, or set the frame yourself
// I set the width to an arbitrary size but it doesn't seem to matter, 
// it will automatically be adjusted by the tableview when you assign it
CGFloat width = 100;
CGFloat height = 500;
footerView.frame = CGRectMake(0, 0, width, height);
// this is the "trick": re-assign the footerView after its size has been updated 
// so that the tableView will show it correctly
tableView.tableFooterView = footerView;

For more information, see Resizing a UITableView’s tableHeaderView

The original answer talked about section footers, not table view footers