Question

Bear with me as I am new to obj-c but I have a UIScrollView and a segmented button that switches between 2 images that are presented in the scrollview. Each image is large and roughly 500Kb, but they are each causing allocations of 20+ MB and crashing my app.

     - (void)viewDidLoad {
 [bvpiscrollview setContentSize:CGSizeMake(768, 2484)];
 UIImage *loadBvImage = [UIImage imageNamed:@"bpi_1536x4965v2.png"];
 bvpiimg.image = loadBvImage;
 [loadBvImage release];
 [super viewDidLoad];
}
-(UIView *)viewForZoomingInScrollView:bvpiscrollview{
 return bvpiimg;
}

-(IBAction)pidonebutton{
 [self.view removeFromSuperview];
}

-(IBAction)segmentedControlIndexChanged{
 switch (self.segmentedControl.selectedSegmentIndex)
 {
  case 0:
   [bvpiscrollview setContentSize:CGSizeMake(768, 2484)];
   UIImage *loadBvImage = [UIImage imageNamed:@"bpi_1536x4965v2.png"];
   bvpiimg.image = loadBvImage;
   [loadBvImage release];
   break;
  case 1:
   [bvpiscrollview setContentSize:CGSizeMake(768, 2556)];
   UIImage *loadMpImage = [UIImage imageNamed:@"mpi_1536x5110v2.png"];
   bvpiimg.image = loadMpImage;
   [loadMpImage release];
  default:
   break;

 }
}
- (void)dealloc {
 [bvpiimg release];
 [bvpiscrollview release];
 [segmentedControl release];
    [super dealloc];
}
@end

Answer 1

A 500k RGBA image would be about 350 pixels square. A 1536 x 5110 pixel RGBA image is about 31.4 MB. You seem to be confusing image size with file size.

The largest size supported across all iOS devices is 1024 pixels on a side, although some support larger dimensions. Try cutting up your large images into smaller tiles before adding them to a view in the view hierarchy. You can cut the image up at runtime with a series of calls to CGImageCreateWithImageInRect. I usually choose 512 pixel or smaller tiles.