I'm looking for the name of a technique to cut out an "uninteresting" part of a photograph. The example I'm thinking of is of a guy on the left of a photograph and a tower on the right. The middle part of the photo is then taken away and the remaining parts are stitched together so that the guy appears to be near the tower.
What you are thinking of is seam carving. The example you are thinking of comes from the Wikipedia article of the same name. Photoshop implements this and calls it "Content-aware scaling" and the GIMP calls it "Liquid Rescale".
There are several key phrases for software which does this automatically:
- "seam carving" — the basic technique for automatically dividing up an image based on features in the image;
- "content aware", as in "content aware fill", "content aware scale", and "content aware move" — software features which use seam carving in image manipulation
- "liquid", as in "liquid resize" or "liquid rescaling" — basically the same, but with a fancier name.
The manual operations behind this are, as AJ says, compositing and stitching. The automated algorithms are pretty slick and can save a lot of effort, although you'll also want to keep a careful eye on the results and be prepared for manual touchup.
Sounds like stitching, but it could be accomplished through a few different types of compositing as well. For the guy, you could simply extract him as a layer and composite him back in to the image. So either stitching (which would be blending the two parts of the image together, or compositing, which would be separating to layers and then using the layers together.