Create thumbnails for a bunch of PDFs

thumbnails.sh

#!/bin/bash

# This will convert PDF atlases to .pngs and then convert them back to .PDF, now rasterized.
# Use this script to flatten PDF exports from QGIS so you can generate thumbnails for the Mapfolio

### DEPENDENCIES
# This script uses parallel, imagemagick and ghostscript. 
# To install: brew install imagemagick && brew install parallel && brew install gs
# Please note: Ghostscript does not automatically come installed with imagemagick.

## All files thumbnail conversion

ls -1 *.pdf | parallel convert '{}' -colorspace RGB -resize 600x400 -border 158.5x0 -background white -alpha remove -opaque none '{.}_thumb.jpg'

ls -1 *.pdf | parallel convert '{}' -colorspace RGB -resize 300x200 -border 79.5x0 -background white -alpha remove -opaque none '{.}_small.jpg'

## The -border adds grey spaces to the side for correct viewing the mapfolio.
## NOTE: The border widths specified apply to *EACH SIDE*, so in this case I had to halve the desired width to get the correct overall width.
 
mkdir ../thumbnails

mv *.jpg ../thumbnails

echo "Done! Files moved to a new 'Thumbnails' folder"

still need to modify this so that it runs on PDF | PNG | all other image types at the same time instead of just PDF. Should be simple but my knowledge of such things is basic.