Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
branch: master

Fetching latest commit…

Octocat-spinner-32-eaf2f5

Cannot retrieve the latest commit at this time

..
Octocat-spinner-32 README.md
Octocat-spinner-32 appcrush.rb
README.md

Blog post: http://idevrecipes.com/2010/12/06/extracting-images-from-apps-in-the-appstore

To recreate features of existing apps, we can use a big clue: the images an app uses. This will often give us insight into how the feature was built.

You can right click on an App in iTunes and see the app’s .ipa file.

image

An .ipa file is just a zip file that is easily expanded resulting in a Payload folder that has the actual .app.

image

But we can’t just double click on the images and open them in something like Preview.app.

image

During app compilation Xcode optimizes all images so they aren’t readable by standard tools like Preview.app.

We need to undo the optimization and restore the images back to their original form.

The tool that the SDK uses to optimize the images is pngcrush and starting with the 3.2 SDK, Apple added the ‘revert-iphone-optimizations’ option to undo this optimization.

I wrote a quick ruby script called appcrush that automates this process.

Point appcrush at an .ipa file from the iTunes AppStore and it:

  • expands the zip file
  • finds all the images
  • runs pngcrush with the revert-iphone-optimizations option on each image

    appcrush '/Users/boctor/Music/iTunes/Mobile Applications/iBooks.ipa'

Blog post: http://idevrecipes.com/2010/12/06/extracting-images-from-apps-in-the-appstore

Something went wrong with that request. Please try again.