image.md

Image Tools

convert(1)

Supported Formats:

identify -list format

Image Conversions:

convert in.jpg out.png                                     # jpg to png. 
convert -background none in.svg out.png                    # svg to png with transparency
convert -trim in.jpg out.jpg                               # trim whitespace around image
convert -trim -fuzz 40% in.jpg out.jpg                     # trim more whitespace around image
convert -scale 50% in.gif out.png                          # scale down to 50% and convert
convert -resize 200x100 in.png out.png                     # scale and keep aspect ration (target size might differ)
convert -crop 500x900+50+100 in.png out.png                # crop from top-left 50x100 with width 500 and height 900
convert -extent 128x128 -gravity center in.png out.png     # extend image with whitespace and center
convert -strip in.jpg out.jpg                              # strip metadata
convert -fill white -colorize 50% in.jpg out.jpg           # fade image 50% transparent

Convert Image to SVG:

convert image.png image.pnm
potrace image.pnm -s -o image.svg

identify(1)

Describes the format and characteristics of one or more image files

identify -verbose image.jpg
identify animated.gif                                      # discover number of frames

exiftool(1)

exiftool image.jpg
exiftool -ext jpg                                          # metedata for all *jpg files in current dir
exiftool -all= -overwrite_original image.jpg               # remove all metadata of a image file
exiftool -gps:all= \*.jpg                                   # remove all GPS metadata of *jpg files in current dir

Image Best Practices

Encode Image as Data URI

convert image.png - | openssl enc -base64 -A | sed -e 's/^/data:image\/png;base64,/'

Image Management

Distribution of file extensions

while read f; do echo ${f##*.}; done < <(fd -t f) | sort | uniq -c | sort