iOS：压缩图片详解手机开发

    UIImage*img= [self imageWithImageSimple:image scaledToSize:CGSizeMake(210.0, 210.0)];//压缩图片   
       
    - (UIImage*)imageWithImageSimple:(UIImage*)image scaledToSize:(CGSize)newSize   
    {   
         // Create a graphics image context   
         UIGraphicsBeginImageContext(newSize); // Tell the old image to draw in this newcontext, with the desired   
           
         // new size   
         [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];   
           
         // Get the new image from the context   
         UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();   
            
         // End the context   
         UIGraphicsEndImageContext();   
            
         // Return the new image.   
         return newImage;   
    }