How do I create a more efficient portrait gallery using Cocos2d? - cocos2d-iphone

Question

I'm building an app that has gallery of portraits (like a museum) and my character(s) walk past them from left-to-right-to-left. My portrait (images) are all 2048x2048. I haven't reduced their size yet because I want to make sure they can be used for the iPad version. I know their large size is an issue because it crashes when I try to load all of them at once (and it takes a long time to launch even with only 10 images).
That being said, my real issue is trying to create an efficient method for adding/removing them (sprites) as needed. I came up with something that works but it is clearly not the best way to do this.
I am hoping someone can suggest a more efficient approach.
Here is my code. You can assume another method takes care of loading the images into a mutable array called framedSprites (except I can only load 10 at a time because of the size/crashing). The following method (checkPosition) is called every time the screen position changes (via a TouchMoved swipe). As I see it, I will have to create similar statements for each image/portrait in the array (very inefficient and time consuming)...
-(void)checkPosition {
CGSize winSize = [CCDirector sharedDirector].winSize;
for (CCSprite *sprite in framedSprites) {
if (sprite.tag == 2) {
if ((sprite.position.x > 2000.0f)&&(sprite.position.x < 2010.0f)) {
CCSprite *portrait = (CCSprite *)[_backgroundNode getChildByTag:0];
if (portrait.tag == 0) {
NSLog(#"Removing a Portrait Left 2 Places From This One");
[_backgroundNode removeChildByTag:0 cleanup:YES];
}
}
if ((sprite.position.x > 1980.0f)&&(sprite.position.x < 1990.0f)) {
CCSprite *portrait = (CCSprite *)[_backgroundNode getChildByTag:0];
if (portrait == nil) {
CCSprite * framedSprite = (CCSprite *)[framedSprites objectAtIndex:0];
NSLog(#"Adding a Portrait Left, 2 Places From This One");
framedSprite.position = ccp(600,winSize.height/2); //figuring these positions is also not efficient and time consuming
[_backgroundNode addChild:framedSprite z:0 parallaxRatio:ccp(0.4f,0.5f) positionOffset:framedSprite.position];
}
}
}
}
}

Answer 1

You should only need to have 3 images loaded at any one time to allow scrolling in either direction (assuming you're not also allowing movement in the y direction). The one on display, one either side as a buffer and then lazy load and replace as needed.
If you don't need to see the entire image at once you could also consider cutting it into tiles using a free tool like Tilen (http://itunes.apple.com/gb/app/tilen/id409199185?mt=12) and then loading the tiles as required.