$ ./node_modules/.bin/pngcrush 

/home/munter/falcon/client/node_modules/pngcrush-installer/bin/pngcrush.js:13
    throw err;
          ^
Error: Command failed: 
 | pngcrush 1.7.66
 |    Copyright (C) 1998-2002, 2006-2013 Glenn Randers-Pehrson
 |    Portions copyright (C) 2005       Greg Roelofs
 | This is a free, open-source program.  Permission is irrevocably
 | granted to everyone to use this version of pngcrush without
 | payment of any fee.
 | Executable name is pngcrush
 | It was built with libpng version 1.5.17, and is
 | running with  libpng version 1.5.17 - June 27, 2013

 |    Copyright (C) 1998-2004, 2006-2013 Glenn Randers-Pehrson,
 |    Copyright (C) 1996, 1997 Andreas Dilger,
 |    Copyright (C) 1995, Guy Eric Schalnat, Group 42 Inc.,
 | and zlib version 1.2.8, Copyright (C) 1995-2013,
 |    Jean-loup Gailly and Mark Adler.
 | It was compiled with gcc version 4.6.3.


If you have modified this source, you may insert additional notices
immediately after this sentence.
Copyright (C) 1998-2002, 2006-2013 Glenn Randers-Pehrson
Portions copyright (C) 2005       Greg Roelofs

DISCLAIMER: The pngcrush computer program is supplied "AS IS".
The Author disclaims all warranties, expressed or implied, including,
without limitation, the warranties of merchantability and of fitness
for  any purpose.  The Author assumes no liability for direct, indirect,
incidental, special, exemplary, or consequential damages, which may
result from the use of the computer program, even if advised of the
possibility of such damage.  There is no warranty against interference
with your enjoyment of the computer program or against infringement.
There is no warranty that my efforts or the computer program will
fulfill any of your particular purposes or needs.  This computer
program is provided with all faults, and the entire risk of satisfactory
quality, performance, accuracy, and effort is with the user.

LICENSE: Permission is hereby irrevocably granted to everyone to use,
copy, modify, and distribute this computer program, or portions hereof,
purpose, without payment of any fee, subject to the following
restrictions:

1. The origin of this binary or source code must not be misrepresented.

2. Altered versions must be plainly marked as such and must not be
misrepresented as being the original binary or source.

3. The Copyright notice, disclaimer, and license may not be removed
or altered from any source, binary, or altered source distribution.


usage: pngcrush [options] infile.png outfile.png
       pngcrush -e ext [other options] file.png ...
       pngcrush -d dir/ [other options] file.png ...
       pngcrush -n -v file.png ...
options:
      -already already_crushed_size [e.g., 8192]
         -bail (bail out of trial when size exceeds best size found
    -bit_depth depth (bit_depth to use in output file)
      -blacken (zero samples underlying fully-transparent pixels)
        -brute (use brute-force: try 138 different methods [11-148])
            -c color_type of output file [0, 2, 4, or 6]
            -d directory_name/ (where output files will go)
 -double_gamma (used for fixing gamma in PhotoShop 5.0/5.02 files)
            -e extension  (used for creating output filename)
            -f user_filter [0-5] for specified method
          -fix (fix otherwise fatal conditions such as bad CRCs)
        -force (write a new output file even if larger than input)
            -g gamma (float, e.g., 0.45455)
      -huffman (use only zlib strategy 2, Huffman-only)
         -iccp length "Profile Name" iccp_file
         -itxt b[efore_IDAT]|a[fter_IDAT] "keyword"
         -keep chunk_name
            -l zlib_compression_level [0-9] for specified method
         -loco ("loco crush" truecolor PNGs)
            -m method [1 through 150]
          -max maximum_IDAT_size [default 8192]
          -mng (write a new MNG, do not crush embedded PNGs)
            -n (no save; doesn't do compression or write output PNG)
          -new (Use new default settings (-force and -reduce))
 -newtimestamp (Reset file modification time [default])
       -nobail (do not bail out early from trial -- see "-bail")
  -nofilecheck (do not check for infile.png == outfile.png)
     -nolimits (turns off limits on width, height, cache, malloc)
     -noreduce (turns off "-reduce" operations)
          -old (Use old default settings (no -force and no -reduce))
 -oldtimestamp (Do not reset file modification time)
           -ow (Overwrite)
   -plte_len n (obsolete; positive "n" enables palette reduction)
            -q (quiet)
       -reduce (do lossless color-type or bit-depth reduction)
          -rem chunkname (or "alla" or "allb")
-replace_gamma gamma (float, e.g. 0.45455) even if it is present.
          -res resolution in dpi
          -rle (use only zlib strategy 3, RLE-only)
         -save (keep all copy-unsafe PNG chunks)
         -srgb [0, 1, 2, or 3]
         -ster [0 or 1]
         -text b[efore_IDAT]|a[fter_IDAT] "keyword" "text"
   -trns_array n trns[0] trns[1] .. trns[n-1]
         -trns index red green blue gray
            -v (display more detailed information)
      -version (display the pngcrush version)
            -w compression_window_size [32, 16, 8, 4, 2, 1, 512]
            -z zlib_strategy [0, 1, 2, or 3] for specified method
         -zmem zlib_compression_mem_level [1-9, default 9]
        -zitxt b|a "keyword" "lcode" "tkey" "text"
         -ztxt b[efore_IDAT]|a[fter_IDAT] "keyword" "text"
            -h (help and legal notices)
            -p (pause)

    at ChildProcess.exithandler (child_process.js:548:15)
    at ChildProcess.EventEmitter.emit (events.js:99:17)
    at maybeClose (child_process.js:646:16)
    at Socket.ChildProcess.spawn.stdin (child_process.js:823:11)
    at Socket.EventEmitter.emit (events.js:96:17)
    at Socket._destroy.destroyed (net.js:358:10)
    at process.startup.processNextTick.process._tickCallback (node.js:245:9)