images.md

Batch convert a bunch of images

# Get a bunch of .jpg files and convert them to png
mogrify -format png *.jpg

Batch resize a bunch of images

# Might be something like:
convert -resize 50% *.png
# Or even better with an xargs fine graining command
mkdir _resized
find . -maxdepth 1 -iname "*.jpg" | xargs -L1 -I{} convert -resize 50% "{}" _resized/"{}"

Convert a PDF to a JPG

# gs (GhostScript) and gm (GraphicsMagick) are required in order to make it work
# Take the first page and make a thumbnail out of it
gm convert -size 128x128 '/path/to/document.pdf[0]' -resize 128x128 +profile "*" '/path/to/PREVIEW.jpg

Convert multiple JPGs to a single PDF

# as simple as:
convert page1.jpg page2.jpg pageN.jpg  manual.pdf

Convert a HTML to a JPG

# html2ps (html2ps), gs (GhostScript) and gm (GraphicsMagick) are required in order to make it work
# Take the first page and make a thumbnail out of it
gm convert -size 128x128 '/path/to/document.pdf[0]' -resize 128x128 +profile "*" '/path/to/PREVIEW.jpg 2>/dev/null
## 2>/dev/null to avoid '*** Error opening thumb*' error lines [CentOS 6.8 did it]

Strip EXIF information from a photo

# All jpg files
exiftool -all= *.jpg
# Single file
exiftool -all= singlefile.jpg