Android XXHDPI Resizer (Tested on OS X Mavericks)

resizer-xxhdpi.sh

#!/bin/bash

f=$(pwd)

mkdir drawable-mdpi drawable-hdpi drawable-xhdpi drawable-xxhdpi 

# fake argv and argc in bash
argc=$#; argv[0]=$0 # argv[0] is a prog name
for foo in $( seq $argc )
do
  eval "argv[${foo}]=\$${foo}"
  filename=${argv[$foo]}
  
  width=$(sips -g pixelWidth $filename | tr -d '\n' | awk '{ print $NF }')
  sips --resampleWidth $(($width/3)) "${f}/${filename}" --out "${f}/drawable-mdpi/${filename}"
  sips --resampleWidth $(($width/2)) "${f}/${filename}" --out "${f}/drawable-hdpi/${filename}"
  sips --resampleWidth $(($width/3*2)) "${f}/${filename}" --out "${f}/drawable-xhdpi/${filename}"
  sips --resampleWidth $width "${f}/${filename}" --out "${f}/drawable-xxhdpi/${filename}"
done

Tio, havies vist aquesta lib?

En principi arregla el teu problema no?

^_^

https://github.com/asystat/Final-Android-Resizer