NSData UIImage 互轉

http://stackoverflow.com/questions/14133366/convert-uiimage-to-nsdata-and-save-with-core-data

If PNG image

UIImage *image = [UIImage imageNamed:@"imageName.png"];
NSData *imageData = [NSData dataWithData:UIImagePNGRepresentation(image)];

If JPG image

UIImage *image = [UIImage imageNamed:@"imageName.jpg"];
NSData *imageData = UIImageJPEGRepresentation(image, 1.0);

You can store it in CoreData like so (this is one possible useful solution):

[newManagedObject setValue:imageData forKey:@"image"];

You can load the data from CoreData like this:

NSManagedObject *selectedObject = [[self yourFetchCOntroller] objectAtIndexPath:indexPath];
UIImage *image = [UIImage imageWithData:[selectedObject valueForKey:@"image"]];

// Set the image to your image view  
yourimageView.image = image;