sampleCache.m

#define TMP NSTemporaryDirectory()

- (NSString*)setFileName:(NSString*)url
{
    NSArray *tokenize = [url componentsSeparatedByString: @"/"];
    NSString *imageFile = [tokenize objectAtIndex:([tokenize count]-1)];
    //NSLog(@"%@",imageFile);
    return imageFile;
}

//saving or get from temporary dir on some void

        NSString *urlImage = "URL OF IMAGE";
        
        NSString *filename = [self setFileName:urlImage];
        NSString *uniquePath = [TMP stringByAppendingPathComponent:filename];
        
        
                    if(![[NSFileManager defaultManager] fileExistsAtPath:uniquePath])
                    {
                        ShowNetworkActivityIndicator();
                        ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:[NSURL URLWithString:urlImage]];
                        [request setTag:x];
                        [request setDelegate:self];
                        [request startAsynchronous];
                    }else
                    {
                        //do somethink if file exist
                    }