Dependencies: imagemagick The idea here is that you have a folder with uncompressed images that use two identifiers in the filename. Using imagmick compressing and converting .png's to .jpg's will move them over to the compressed folder. The two filename identifires are Size "thumb, md, lg" and Retina "noneretina, 2x". If you're using awesome sc…

bash.sh

#!/bin/bash

#---------------------------------------------#
#
# VARIABLES
#
BGCOLOR="#f6f6f6" #Background color to use when flattening transparent areas of png
thumbnail='185' #Thumbnail image width
medium='650' #Medium image width
large='1000' #Large image width
imageDirectoryPath='./img/portfolio' #Path to image directory which will be compressed
moveToCompressedFolder='mv .tmp/*.jpg .tmp/../compressed/' #Move compressed images to compressed folder
clearTempFolder='rm -R .tmp/*.png' #Clearout temp folder after each process is complete
#---------------------------------------------#

cd $imageDirectoryPath 	#change directory to exicute script in uncompressed folder
mkdir .tmp;     	#making temp derectory
mkdir compressed;   #making compressed derectory so new images have a place to go

#Thumbnails
thumb=`ls | grep '_thumb'` && cp $thumb .tmp/; #grabs file by special filename info and moves them over to temp file
mogrify -format jpg -filter Triangle -define filter:support=2 -thumbnail $thumbnail -quality 100 -unsharp 0.25x0.08+8.3+0.045 -dither None -define jpeg:fancy-upsampling=off -interlace plane -colorspace sRGB -background $BGCOLOR -flatten -path .tmp/ .tmp/*.png
$moveToCompressedFolder;

#Thumbnails _2x
filelist=`ls .tmp/`;
for image_file in $filelist
do
inname=`convert $image_file -format "%[base]" info:`
convert $image_file -set filename:mysize 2x .tmp/${inname}_%[filename:mysize].jpg
done
mogrify -format jpg -filter Triangle -define filter:support=2 -thumbnail $(($thumbnail * 2)) -quality 100 -unsharp 0.25x0.08+8.3+0.045 -dither None -define jpeg:fancy-upsampling=off -interlace plane -colorspace sRGB -background $BGCOLOR -flatten -path .tmp/ .tmp/*_2x.jpg
$moveToCompressedFolder; $clearTempFolder;

#Medium
med=`ls | grep '_md'` && cp $med .tmp/;
mogrify -format jpg -filter Triangle -define filter:support=2 -thumbnail $medium -quality 100 -unsharp 0.25x0.08+8.3+0.045 -dither None -define jpeg:fancy-upsampling=off -interlace plane -colorspace sRGB -background $BGCOLOR -flatten -path .tmp/ .tmp/*.png
$moveToCompressedFolder;

#Medium _2x
filelist=`ls .tmp/`;
for image_file in $filelist
do
inname=`convert $image_file -format "%[base]" info:`
convert $image_file -set filename:mysize 2x .tmp/${inname}_%[filename:mysize].jpg
done
mogrify -format jpg -filter Triangle -define filter:support=2 -thumbnail $(($medium * 2)) -quality 100 -unsharp 0.25x0.08+8.3+0.045 -dither None -define jpeg:fancy-upsampling=off -interlace plane -colorspace sRGB -background $BGCOLOR -flatten -path .tmp/ .tmp/*_2x.jpg
$moveToCompressedFolder; $clearTempFolder;

# #Large
lg=`ls | grep '_lg'` && cp $lg .tmp/;
mogrify -format jpg -filter Triangle -define filter:support=2 -thumbnail $large -quality 100 -unsharp 0.25x0.08+8.3+0.045 -dither None -define jpeg:fancy-upsampling=off -interlace plane -colorspace sRGB -background $BGCOLOR -flatten -path .tmp/ .tmp/*.png
$moveToCompressedFolder;

#Large _2x
filelist=`ls .tmp/`;
for image_file in $filelist
do
inname=`convert $image_file -format "%[base]" info:`
convert $image_file -set filename:mysize 2x .tmp/${inname}_%[filename:mysize].jpg
done
mogrify -format jpg -filter Triangle -define filter:support=2 -thumbnail $(($large * 2)) -quality 100 -unsharp 0.25x0.08+8.3+0.045 -dither None -define jpeg:fancy-upsampling=off -interlace plane -colorspace sRGB -background $BGCOLOR -flatten -path .tmp/ .tmp/*_2x.jpg
$moveToCompressedFolder; $clearTempFolder;

echo 'Completed Successfully';

rm -R .tmp; #removes temp directory