OS X port of img2sf: A script to generate screenfetch ASCII from an image. Original img2sf project link: https://github.com/cbarox/scripts/tree/master/img2sf

README

Dependencies: img2xterm (not available via Homebrew -- you will need to build from source, see below)
Rossy's img2xterm project link:  https://github.com/rossy/img2xterm

Notes:  I had to re-install ImageMagick for img2xterm to work properly.

Instructions:
$ brew update
$ brew reinstall imagemagick
$ git clone https://github.com/rossy/img2xterm.git
$ cd img2xterm && make && make install

Original img2sf raw script:  https://raw.githubusercontent.com/cbarox/scripts/master/img2sf/img2sf
Below is how I modified the img2sf script to work with OS X (tested on version 10.10.4):

Also:
Since OS X uses BSD sed, which doesn't support the -i flag, I originally modified the script to use GNU sed, which I installed via Homebrew.  However, I have since modified the script to support the BSD version of sed that ships natively with OS X (or Xcode -- not sure).  I would still advise using gsed, since the use of the -i flag is cleaner and doesn't require as much additional code and/or cleanup.

Changes:
Removed  Line 16:  echo 'startline="0"' > $2
Removed  Line 17:  echo 'fulloutput=(' >> $2
Modified Line 25:  spaces=$(expr "$imgw" - "$nspaces" - "$nup" - "$ndown" 2>/dev/null)
Removed  Line 28:  echo ")" >> $2
Removed  Line 30:  sed -i "0,/%s/{s/%s/ %s/}" "$2"
Added    Line 31:  sed 's/"//g' "$2" > osx.tmp; mv osx.tmp "$2"
Added    Line 32:  sed 's/%s//g' "$2" > osx.tmp; mv osx.tmp "$2"

img2fs.sh

#!/bin/bash

if [ $# -eq 0 ]; then
    echo -e " \n \t ERROR: No arguments provided"
    echo -e " \t USAGE: img2sf <path/to/image> <path/to/output>\n"
    exit 1
fi

imgw=$(convert -print "%w\n" "$1" /dev/null)

# generate the image
TMPFILE="tmp"
img2xterm "$1" > $TMPFILE

# form the output file
IFS=''
cat $TMPFILE |
while read line
do
    nspaces=$(grep -o " " <<< "$line" | wc -l)
    nup=$(grep -o "ΓûÇ" <<< "$line" | wc -l)
    ndown=$(grep -o "Γûä" <<< "$line" | wc -l)
    spaces=$(expr "$imgw" - "$nspaces" - "$nup" - "$ndown" 2>/dev/null)
    printf "\"%s%${spaces}s %%s\"\n" "$line" "" >> $2
done

sed 's/"//g' "$2" > osx.tmp; mv osx.tmp "$2"
sed 's/%s//g' "$2" > osx.tmp; mv osx.tmp "$2"

# clean up
rm $TMPFILE