To describe what a joiner is it is probably best to show you an example of the most popular kind of joiner image that you are likely to see: the PANORAMA.

The panoramic image is produced by taking a series of overlapping images in sequence by rotating your viewpoint along the horizon. Leeds Castle, Kent:


This image was created from seven images taken left to right and photoshopped together.


There are however a variety of procedures to create new and exciting joiner photographs of a scene as with this one currently used in the main page header, Lucy in the Louvre:


This is not a Panorama. For want of a better name we can call it a ROLLER PHOTO. The difference in this image is that it is a photographic series taken parallel to the wall. That is why the wall appears flat and we appear to be looking directly in to three doorways. It is almost like a flat technical drawing but it is a photograph and those different viewpoints should unconsciously alert us to something different going on. It's also a bit bigger than it appears here, around 5 ft long.

Here is another taken of a Street in Buckinghamshire, which includes both Panoramic and Roller features: