I would like to help others who use this plugin, but want to have a faster load speed.
This plugin uses the full size images from galleries, so it's a lot better to have images just the size of the slideshow.
For that I used timthumb.php and just a small modification of the plugin in includes/dfcg-gallery-core.php, line 467:
$output_temp = get_bloginfo('template_url').'/timthumb.php?zc=1&q=80&a=c&src='.$image.'&w=538&h=250&siteName=devsally'; $output = $output_temp;//$image; //as we have the full size image urls, we will use timthumb to minimize them; //it'a a lot more efficient to have smaller images
As you can see, I have timthumb.php in the theme folder. Each should configure timthumb as needed; in this case, I crop the images, but uzinc zc=2 will scale down images and fill the spaces with black color.
You can see it on http://drumliber.ro.