1-Step Gallery PHP script
I wanted a quick way to be able to share images with people. This is a single index.php file that, when dropped into a folder on a web server with images in it, will auto-generate a gallery at that web address.
The key interface is a size slider that allows the user to adjust the size of the images from thumbnail all the way to the full width of the browser window.
When uploading, a few configuration options can be set within the file, including the ability to use each filename, stripped of underscores/dashes, as a caption.