UIImage, check if contain image

You can check if it has any image data.

UIImage* image = [[UIImage alloc] init];

CGImageRef cgref = [image CGImage];
CIImage *cim = [image CIImage];

if (cim == nil && cgref == NULL)
{
    NSLog(@"no underlying data");
}
[image release];

Swift Version

let image = UIImage()

let cgref = image.cgImage
let cim = image.ciImage

if cim == nil && cgref == nil {
    print("no underlying data")
}

Check for cgImage or ciImage, in Swift 3

public extension UIImage {

  public var hasContent: Bool {
    return cgImage != nil || ciImage != nil
  }
}

CGImage: If the UIImage object was initialized using a CIImage object, the value of the property is NULL.

CIImage: If the UIImage object was initialized using a CGImageRef, the value of the property is nil.