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.cgImagelet cim = image.ciImageif 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.