Making ID Photos with GIMP

You can make ID photos cheaply using GIMP:

1. Take a head-and-shoulders picture with your digital camera.
2. Load or paste the image into GIMP.
3. Rotate the image, if necessary, to a portrait orientation using menu item Image / Transform / Rotate 90 ….
4. Shrink the image to one quarter the original size using menu item Image / Scale Image. You have to calculate the required pixel size because the Scale Image doesn't have a "shrink by half" function.
5. Create a new image with the dimensions of the original image, in landscape orientation.
6. Select menu item Image / Configure Grid and set the spacing so that it matches the size of your shrunk image. The idea is to have a grid as per ASCII art below:

   +--+--+--+--+
   |  |  |  |  |
   +--+--+--+--+
   |  |  |  |  |
   +--+--+--+--+
   

7. Select menu item View / Snap to Grid and View / Show Grid.
8. Copy and paste your shrunk image into the new image. You should be able to fit 8 images in one picture. Use the grid to help you position the images in each cell. Positioning all images in the grid's cells also makes it easier to cut the photos after they have been printed.

My camera takes 3072 x 2304 pixel images (or 6:4.5 ratio), so if I use 15cm x 10cm (6:4 ratio) paper, the images on the left and right edges would be cropped unless I further shrink the images by 5%.