If you know what lightbox.js is and want it for your Pixelpost this it the addon for you
For the rest please read on.
What is this lighbox?
Hop over to http://serennz.cool.ne.jp/sb/sp/lightbox/
How can I use it in my pixelpost
If you use the AutoResize addon and keep the full size image - you can use this addon and get the same cool effects when visitors see your fullsize image
How to use this addon
#1 Unzip the files in your addons folder
#2 Add <FULLSIZE_LINK> to your image_template.html at the place you want the Fullsize link to appear
#3 Add <LIGHTBOX_JS_CSS> to your image_template.html just before </head> (thats a safe place)
#4 Enjoy/Complain as the case may be
(may not be worksafe for some)
Usual disclaimers apply