I'm at a bit of a loss. I've used the layer property of UIView to round the corners of multiple elements in my app. However, this one UIImageView is simply not complying. Not sure what I am missing.

The UIImageView (called previewImage) is contained in a Table View Cell. I've tried setting the cornerRadius property multiple location (in the cell itself and in the controller that creates the cell) to no avail.

static NSString *CellIdentifier = @"MyTableViewCell";

MyTableViewCell *cell = (MyTableViewCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
    NSArray *topLevelObjects = [[NSBundle mainBundle] loadNibNamed:CellIdentifier owner:self options:nil];
    cell = [topLevelObjects objectAtIndex:0];
    cell.previewImage.layer.cornerRadius = 20; //Made it 20 to make sure it's obvious.
}

Is there something about the way cells are loaded that I'm missing?