TinyGallery is a one file PHP image gallery, which doesn't need any database or creates files on your server. It only displays the images in a folder (including subfolders if you want this). So it's great if you want to share some images with your friends and don't want to install a big gallery script.
Using some nice javscript effects you can view additional informations about the images, like filesize, dimensions, create date, etc. German website but the script is in English.