Make a Mini Planet

Goal

Turn a panoramic or regular landscape photo into a mini planet, like this one:

by nate bolt, on Flickr

Walkthrough

1. I chose a picture of some sheep in a field. This picture has a fairly flat horizon, featureless sky, and a bottom section without structures, which is good because the bottom will get distorted a lot in order to make it the center of my planet. I'm pretty sure that a picture without an uninterrupted band of sky at the top won't look good, but I can't definitively say so. Open this picture in GIMP.

2. Duplicate the layer so you have the option of starting over at any time.
3. To keep a version of the picture you can edit again later, save it in xcf format, GIMP's native format that preserves all the image's layers. Go to File > Save and in the popup window, choose a folder and set the name to planet.xcf (only the .xcf part matters). Click File > Save often during every project, in case GIMP or a plugin crashes.
4. Click Filters > Distorts > Polar Coordinates... in the menu bar. Expect this plugin to take longer than expected to load. It brings you to a window with a preview and five configuration options. Set the circle depth at 100% to give the planet a circular border, offset angle at 278.98 to put the flagpole at the top, Map backwards unchecked, Map from top unchecked, To polar checked. Then click OK to apply the filter.
   

Use Liquid Rescale to make an image fit your desktop

My camera takes pictures with an aspect ratio of 4:3, meaning if you shrank the picture so it was 4 inches across, it would be 3 inches high. Unfortunately, that means if I used it as the desktop background on a widescreen, 1080p monitor, either the top and bottom of the picture would get cut off or there would be blank space on the sides.

Goal

I want to make the picture fit the display perfectly without cropping it. I have two options in GIMP: use the traditional scale tool, which will stretch the image horizontally, or the Liquid Rescale plugin, which is designed to leave a photo's important features intact while stretching the less important areas. The scale tool causes a lot of distortion, though, while Liquid Rescale keeps things like faces, letters and buildings their original shape. Liquid Rescale comes with lisanet's version of GIMP.

Walkthrough

1. I found a picture of a damselfly that I wanted to resize. Find your picture, check that it's a different shape from your display, right-click it in the Finder, and select Open With > GIMP.
2. Go to the list of layers on the right side of the GIMP window, and click the Duplicate Layer button. If you keep making changes and then decide you don't like it anymore, you can delete the layer you modified and revert to your original photo.