Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I am trying to figure out how to do batch processing with ImageAlpha. I really like this program, but I cannot figure out how to batch process. Just to be clear, I am trying to convert several images from PNG24 to PNG8.

share|improve this question

migrated from Sep 15 '12 at 0:13

This question came from our site for professional and enthusiast programmers.

This doesn't seem to be a programming question, and is therefore off-topic. You might want to try Super User, but you will have to add a lot more detail than "cannot figure out how to do this" before reposting. – Josh Caswell Sep 14 '12 at 17:35
up vote 4 down vote accepted

According to the ImageAlpha site:

Batch processing
ImageAlpha is mostly based on pngquant. You'll find compiled pngquant executable in directory.

e.g. -ext 8bit.png yourInputImage.png 

For more options run: -h


share|improve this answer
Thank you for the help but my problem is that I don't know how to run the executable. I can get as far as opening the executable but then where to go from there I have no idea. When I open the pngquant executable it says "process completed logout" and I can't type anything more in that window. – Stephen Sep 14 '12 at 21:06
You execute the application from Terminal. Run (from Applications/Utilities) and use the commands above. Note that you must either cd to the directory that contains first or prepend the path...for example, if is in /Applications, try this in Terminal: /Applications/ -h – George Profenza Sep 14 '12 at 21:20
It looks like you've never used the commandline before on osx. There are plenty of tutorials out there. The above will become trivial once you've understood the basics (navigating to a directory, running an application, using flags) – George Profenza Sep 14 '12 at 21:24
I tried doing all of the things that have been recommended and after I run the the executable I followed this tuturial <…; and it keeps saying pngquant: command not found? – Stephen Sep 14 '12 at 21:37
either it's a typo: should be pngquant, not ngquant, either you're trying to run the command from a path different from where pngquant lives. Note that the tutorial you've picked is for Windows and CommandPrompt uses different commands from Terminal (although a few are similar). Maybe it's easier to add pngquant to the system path so you can call the application from anywhere on the system. Try this in Terminal: sudo pico ~/.bash_profile - this should open a text editor. Add/Append this to the file export PATH=/Applications/$PATH then exit (Ctrl+X) & save – George Profenza Sep 14 '12 at 21:42

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .