Load image from photo library

1. How can I load an image from photo library and show it in 开发者_Python百科imageView?
2. How can I change image to black and white?

If you want to load an image from photo library, you have to use UIImagePickerController class. Refer this Link

To convert image form UIImagePickerController to black and white you can use this code:

UIImage *originalImage = [info objectForKey:UIImagePickerControllerOriginalImage]; // this image we get from UIImagePickerController

CGColorSpaceRef colorSapce = CGColorSpaceCreateDeviceGray();
CGContextRef context = CGBitmapContextCreate(nil, originalImage.size.width, originalImage.size.height, 8, originalImage.size.width, colorSapce, kCGImageAlphaNone);
CGContextSetInterpolationQuality(context, kCGInterpolationHigh);
CGContextSetShouldAntialias(context, NO);
CGContextDrawImage(context, CGRectMake(0, 0, originalImage.size.width, originalImage.size.height), [originalImage CGImage]);

CGImageRef bwImage = CGBitmapContextCreateImage(context);
CGContextRelease(context);
CGColorSpaceRelease(colorSapce);

UIImage *resultImage = [UIImage imageWithCGImage:bwImage]; // This is result B/W image.
CGImageRelease(bwImage);