Most memory efficient way to save a photo to disk on iPhone?

Question

From profiling with Instruments I have learned that the way I am saving images to disk is resulting in memory spikes to ~60MB. This results in the

Answer 1

Using UIImageJPEGRepresentation requires that you have the original and final image in memory at the same time. It may also cache the fully rendered image for a while, which would use a lot of memory.

You could try using a CGImageDestination. I do not know how memory efficient it is, but it has the potential to stream the image directly to disk.

+(void) writeImage:(UIImage *)inImage toURL:(NSURL *)inURL withQuality:(double)inQuality {
    CGImageDestinationRef destination = CGImageDestinationCreateWithURL( (CFURLRef)inURL , kUTTypeJPEG , 1 , NULL );
    CFDictionaryRef properties = (CFDictionaryRef)[NSDictionary dictionaryWithObject:[NSNumber numberWithDouble:inQuality] forKey:kCGImageDestinationLossyCompressionQuality];
    CGImageDestinationAddImage( destination , [inImage CGImage] , properties );
    CGImageDestinationFinalize( destination );
    CFRelease( destination );
}