how to compress image in iphone?

Question

I m taking images from photo library.I have large images of 4-5 mb but i want to compress those images.As i need to store those images in local memory of iphone.for using le

Answer 1

UIImageJPEGRepresentation(UIImage,Quality);

1.0 means maximum Quality and 0 means minimum quality.

SO change the quality parameter in below line to reduce file size of the image

NSData* data = UIImageJPEGRepresentation(image,1.0);

Answer 2

You can choose a lower quality for JPEG encoding

NSData* data = UIImageJPEGRepresentation(image, 0.8);

Something like 0.8 shouldn't be too noticeable, and should really improve file sizes.

On top of this, look into resizing the image before making the JPEG representation, using a method like this:

+ (UIImage *)imageWithImage:(UIImage *)image scaledToSize:(CGSize)newSize {
    UIGraphicsBeginImageContext(newSize);
    [image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();    
    UIGraphicsEndImageContext();
    return newImage;
}

Source: The simplest way to resize an UIImage?

Answer 3

NSData *UIImageJPEGRepresentation(UIImage *image, CGFloat compressionQuality);

OR

NSData *image_Data=UIImageJPEGRepresentation(image_Name,compressionQuality);

return image as JPEG. May return nil if image has no CGImageRef or invalid bitmap format. compressionQuality is 0(most) & 1(least).