iPhone - UIImage imageScaledToSize Memory Issue

Question

I have done research and tried several times to release the UIImage memory and have been unsuccessful. I saw one other post on the internet where someone else was having this same issue. Everytime imageScaledToSize is called, the ObjectAlloc continues to climb.

In the following code I am pulling a local image from my resource directory and resizing it with some blur. Can someone provide some help on how to release the memory of the UIImages called....scaledImage and labelImage. This is the chunk of code where the iPhone Intruments has shown to have the ObjectAlloc build up. This chunk of code is called several times with an NSTimer.

//Get local image from inside resource
NSString * fileLocation = [[NSBundle mainBundle] pathForResource:imgMain ofType:@"jpg"];
    NSData * imageData = [NSData dataWithContentsOfFile:fileLocation];
    UIImage * blurMe = [UIImage imageWithData:imageData];

//Resize and blur image
    UIImage * scaledImage = [blurMe _imageScaledToSize:CGSizeMake(blurMe.size.width / dblBlurLevel, blurMe.size.width / dblBlurLevel) interpolationQuality:3.0];
    UIImage * labelImage = [scaledImage _imageScaledToSize:blurMe.size interpolationQuality:3.0];
    imgView.image = labelImage;

Answer 1

You can wrap the calls in an NSAutoreleasePool, where their results will be pooled. Then you can call [pool drain] on that pool and its contents will be released, including the images.

Note however that you will not be able to use the images outside of the NSAutoreleasePool's scope, so you code might want to look something like:

NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

UIImage * scaledImage = [blurMe _imageScaledToSize:CGSizeMake(blurMe.size.width / dblBlurLevel, blurMe.size.width / dblBlurLevel) interpolationQuality:3.0];
UIImage * labelImage = [scaledImage _imageScaledToSize:blurMe.size interpolationQuality:3.0];
UIImage * imageCopy = [[UIImage alloc] initWithCGImage:labelImage.CGImage]; // Gives a non-autoreleased copy of labelImage

[pool drain]; // deallocates scaledImage and labelImage

imgView.image = imageCopy; // retains imageCopy

UPDATE:

If the above is still giving you problems, please see the solution I posted to this question. The question involves rotating an image 90 degrees instead of scaling it, but the premise is the same (it's just the matrix transformation that is different). Using code like in the answer I posted should give you greater control over your memory management and steer you away from using undocumented APIs like _imageScaledToSize.