Force UIImage to decompress

UIImage+JTImageDecode.h

//
//  UIImage+JTImageDecode.h
//
//  Created by james on 9/28/11.
//  http://ioscodesnippet.tumblr.com
//

@interface UIImage (JTImageDecode)
+ (UIImage *)decodedImageWithImage:(UIImage *)image;
@end

UIImage+JTImageDecode.m

//
//  UIImage+JTImageDecode.m
//
//  Created by james on 9/28/11.
//  http://ioscodesnippet.tumblr.com
//

@implementation UIImage (JTImageDecode)

+ (UIImage *)decodedImageWithImage:(UIImage *)image {
    CGImageRef imageRef = image.CGImage;
    // System only supports RGB, set explicitly and prevent context error
    // if the downloaded image is not the supported format
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    CGContextRef context = CGBitmapContextCreate(NULL,
                                                 CGImageGetWidth(imageRef),
                                                 CGImageGetHeight(imageRef),
                                                 8,
                                                 // width * 4 will be enough because are in ARGB format, don't read from the image
                                                 CGImageGetWidth(imageRef) * 4,
                                                 colorSpace,
                                                 // kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Little 
                                                 // makes system don't need to do extra conversion when displayed.
                                                 kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Little); 
    CGColorSpaceRelease(colorSpace);

    if ( ! context) {
        return nil;
    }
    
    CGRect rect = (CGRect){CGPointZero, CGImageGetWidth(imageRef), CGImageGetHeight(imageRef)};
    CGContextDrawImage(context, rect, imageRef);
    CGImageRef decompressedImageRef = CGBitmapContextCreateImage(context);
    CGContextRelease(context);
    
    UIImage *decompressedImage = [[UIImage alloc] initWithCGImage:decompressedImageRef];
    CGImageRelease(decompressedImageRef);
    return [decompressedImage autorelease];
}

@end