ImageMagick and photos for ID cards

I had to make some ID card pictures for my daughter, and the public machine that I usually use for that was down this morning. So, I decided that I would simply take a picture of her, arrange that into a 13x10cm picture, and have it developed (along with other pictures). My first intention was to use the gimp for that, but, I never learned how to use it, and I wouldn't have a simple way to do that again should I need to.

So I went for the command-line approach, with the tool montage from ImageMagick. The pictures should measure 35x45mm in the end. I used the following command-line options:

• -tile 3x2 6 small picture fit on the target paper
• -geometry 700x900 the size of an individual image (not the one of the whole montage); it is a multiple of 35x45 and gives a neat resolution in the end
• -border 8%x5% -bordercolor white to add a neat white border around the pictures. The numbers are computed so that the overall picture respects (around) the 13x10 aspect ratio

In short, that gives this:

montage -tile 3x2 -geometry 700x900 -border 8%x5% \
  -bordercolor white Morgane.jpg +clone +clone \
  +clone +clone +clone target.jpg

The +clone just tell montage to reuse the last picture used.