There's a jQuery plugin out there that puts a dragable bar that lets you pull it to the left or right to show one image or another. You can keep it in the middle to see half of each photo. It's not a "slider". It's great for showing how something has been altered or photoshoped. Is anyone aware of this plugin and know where I can find it?
Update
"Sliders" are the common term for a rotating image carousel. Here are some examples, there ae about a thousand lists of sliders.
What I'm trying to talk about is a bar not unlike the one on the bottom of the post edit screen here on StackOverflow. It allows you to drag a bar towards the left and right to cover/uncover the images in place.