How to easily resize/optimize an image size with iOS?

Question

My application is downloading a set of image files from the network, and saving them to the local iPhone disk. Some of those images are pretty big in size (widths larger tha

Answer 1

A problem that might occur on retina displays is that the scale of the image is set by ImageCapture or so. The resize functions above will not change that. In these cases the resize will work not properly.

In the code below, the scale is set to 1 (not scaled) and the returned image has the size that you would expect. This is done in the UIGraphicsBeginImageContextWithOptions call.

-(UIImage *)resizeImage :(UIImage *)theImage :(CGSize)theNewSize {
    UIGraphicsBeginImageContextWithOptions(theNewSize, NO, 1.0);
    [theImage drawInRect:CGRectMake(0, 0, theNewSize.width, theNewSize.height)];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}