Creating a UIImage from a UIColor to use as a background image for UIButton

I'm creating a colored image like this:

CGRect rect = CGRectMake(0, 0, 1, 1);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context,
                                   [[UIColor redColor] CGColor]);
//  [[UIColor colorWithRed:222./255 green:227./255 blue: 229./255 alpha:1] CGColor]) ;
CGContextFillRect(context, rect);
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

and then use it as the background image of a button:

[resultButton setBackgroundImage:img forState:UIControlStateNormal];

This works great using the redColor, however I want to use an RGB color (as shown in the commented line). When I use the RGB color, the buttons background isn't changed.

What am I missing?