Proper way of saving and loading pictures

I am making a small app where the user can create a game profile, input some data and a picture that can be taken with the camera.

I save most of that profile data with the help of NSUserDefaults, but a friend discouraged me from saving the profile image in NSUserDefault.

What's the proper way to save and retrieve images locally in my a开发者_JAVA百科pp?

You should save it in Documents or Cache folder. Here is how to do it.

Saving into Documents folder:

NSString* path = [NSHomeDirectory() stringByAppendingString:@"/Documents/myImage.png"];

BOOL ok = [[NSFileManager defaultManager] createFileAtPath:path 
          contents:nil attributes:nil];

if (!ok) 
{
    NSLog(@"Error creating file %@", path);
} 
else 
{
    NSFileHandle* myFileHandle = [NSFileHandle fileHandleForWritingAtPath:path];
   [myFileHandle writeData:UIImagePNGRepresentation(yourImage)];
   [myFileHandle closeFile];
}

Loading from Documents folder:

NSFileHandle* myFileHandle = [NSFileHandle fileHandleForReadingAtPath:path];
UIImage* loadedImage = [UIImage imageWithData:[myFileHandle readDataToEndOfFile]];

You can also use UIImageJPEGRepresentation to save your UIImage as a JPEG file. What's more if you want to save it in Cache directory, use:

[NSHomeDirectory() stringByAppendingString:@"/Library/Caches/"]

One way to do this is use the application's document directory. This is specific to a application and will not be visible to other applications.
How to create this:
Just add a static function to App Delegate and use the function where ever the path is required.

- (NSString )applicationDocumentDirectory {
    /
     Returns the path to the application's documents directory.
     */ 
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *basePath = ([paths count] > 0) ? [paths objectAtIndex:0] : nil;
    return basePath;
}

I think this("iphone-user-defaults-and-uiimages") post addresses your issue. Don't save blobs to a property list such as NSUserDefaults. In your case I would write to disk directly instead.