Use SDWebImage. You can download it from below url
https://github.com/rs/SDWebImage
For load 100 images using Asynchronous request
for(int i=0; i<99; i++)
{
strImage=[[res valueForKey:@"result"] objectAtIndex:i];
if ([[strImage lowercaseString] hasSuffix:@".jpg"] || [[strImage lowercaseString] hasSuffix:@".png"])
{
//[HUD show:YES];
NSURL *url=[[NSURL alloc]initWithString:strImage];
NSURLRequest *urlRequest = [NSURLRequest requestWithURL:url];
[NSURLConnection sendAsynchronousRequest:urlRequest queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error)
{
thumbnail.image=[UIImage imageWithData:data];
}];
}
}