Image Manipulation

ImageMagick

Create a PDF from image files

# single image per page
convert a.jpg b.jpg ab.pdf
# 2x2 tiled, landscape
montage *jpg -adjoin -border 0 -tile 2x2 -rotate 90 -page letter -geometry +2+2 example.pdf

Exiftool

Remove metadata from JPEG

exiftool -all= example.jpg

Modify PDF metadata

exiftool file.pdf -Title="Animal Farm" -Author="George Orwell"

ASCII art

Convert JPG to ASCII art

jp2a -b --colors --fill