With JSN ImageShow, its possible to display images of a Joomla gallery or a online gallery service, like Flickr, Picasa, Instagram and ImageShack in a image slideshow on your Joomla website. Also your images of your facebook account can be displayed. JSN ImageShow is ready for desktops and mobiles, comes with multiple layouts and in different languages. A fine feature is the integrated drag and drop mechanism, which allows you to choose your favorite images for the slideshow list in easy way. JoomlaShine provide this image slideshow extension in a free version for Joomla 2.5 and Joomla 3.x. If you want to use it with all features, try on of the two commercial versions.
Magic Slider is a free fullscreen image slideshow module, which is native to Joomla 2.5 and Joomla 3.0. Based on jQuery library, its include all images dynamically on your website. Up to 20 images can be displayed. Every image can be assign by a thumbnail. You can set also a title and a description. Magic Slider supports Google Fonts. The download is free. You can get it on developers website.