Using the wide wind theme or any other non fixed width theme user might have browsers that don't support the width/height of the image on the photo page. Using code from http://www.ollicle.com/projects/jquery/imagefit/eg/ this module scales images to fit their parent container. The resized image is dynamically resized to fit the parent container of the theme in use.
This module may be downloaded from the codex here.
To install, extract the "image_fit" folder from the zip file into your Gallery 3 modules folder.
Afterwards log into your Gallery web site as an administrator and activate the module in the Admin -> Modules menu.
No configuration is required.
Similar modules: Gallery3:Modules:fittoscreen