set-pdf-thumbnails.sh

#!/bin/bash
# Add thumbnails to images. This works well for document images (like PDFs),
# where the top of the image is the most important.

for file in "$@"; do
  # `--cropOffset 0 0` doesn't do anything, so we use a small offset.
  sips \
    -s format png \
    --resampleWidth 512 \
    --cropOffset 0 0.001 \
    --cropToHeightWidth 512 512 \
    "$file" \
    --out "_tmpThumbnail.png" \
    >/dev/null
  fileicon set "$file" "_tmpThumbnail.png"
  rm _tmpThumbnail.png
done