How do I keep images in programmatrically-created UIButtons from being scaled?

I'm creating a series of UIButtons from an NSArray of UIImages with the following:

#define BUTTONWIDTH 66

    for (int i = 0; i < [imgArray count]; i++){
        toolTile = [UIButton buttonWithType:UIButtonTypeRoundedRect];
        buttonRect = CGRectMake((BUTTONWIDTH*i)+i, 0, BUTTONWIDTH, BUTTONWIDTH);
        toolTile.frame = buttonRect;
        toolTile.tag = i;
        [toolTile addTarget:self action:@selector(toolTileClick:) forControlEvents:UIControlEventTouchUpInside];
        toolTile.imageView.contentMode = UIViewContentModeCenter;
        [toolTile setBackgroundImage:[imgArray objectAtIndex:i] forState:UIControlStateNormal];
        [[self view] addSubview:toolTile];
    }

Unfortunately, the images are being scale开发者_Python百科d (blown up) to fill the 66x66 tile. I want them to be centered at 1:1 in the tile- supposedly toolTile.imageView.contentMode = UIViewContentModeCenter should do that. I've tried moving this line before,after the setBackgroundImage: -no luck. What am I missing?

The culprit was using setBackgroundImage:forState:[UIControlState] instead of setImge:forState:[UIControlState].

SetBackgroundImage apparently always scales, SetImage: honors the imageView.contentMode.