One of the most sought after design element in a web site is an image gallery. Their are many ways to execute an image gallery, such as: Widgets, Lightbox, Flash, JQuery, CSS or JS. The best solution for you will depend on your level of skill, and of course the design of your site.
You can create image gallery's with Adobe Bridge. It is not the most sophisticated way to do it, however, it is very simple and will get the job done. In order to use the Bridge Gallery, select the Output Workspace from the top of the Bridge Window. You will then be able to customize it with built in gallery templates (most of which are flash, however their are a couple of html options). All you have to do is add the photos and Bridge Gallery will do all the coding for you.
The Adobe Exchange has a few galleries you can import as widgets. You can customize your widget directly in the exchange and then save the preset to import into Dreamweaver. Very easy and very user friendly. You can customize your imported gallery with CSS applied to the div tags. This will allow your gallery to be cohesive with your site layout.
When is an image gallery appropriate? When you have a showcase of photography. You can also use it for portfolio items. Just remember, if you want your gallery to work on blackberry's, ipads and iphones, you will need to use a non Flash gallery, as they do not support Flash.
Image Gallery Solutions on the web: