iOS - The MIB Optimizer


The MIB Optimizers should ONLY be used for iPhone and iPad MIBs.If you intend to repurpose your iPhone or iPad MIBs for your Android app then you can select the option of "Android Compatible inside the tool.
The MIB Optimizer tool is also NOT currently compatible with our Progressive Downloads feature. 

What is the MIB Optimizer?

The MIB Optimizers is a Mac OS X tool to compress your MIB files (Support for Mac OS 9 and up only). It unpacks the MIB (which is just a zip file), looks at all the images and converts any PNG file it thinks could be a JPEG into a JPEG, which take up less space. It does this by looking at how much transparency is used: if it's almost none, it can be a JPEG. Then it runs some optimizations on the JPEGs—basically the equivalent of selecting Good as the quality setting in the Mag+ Plug-in settings—and the remaining PNGs, and then packs it back up. 

So how much space can it save? Depends on how your MIB was made and what's in it, but we often see 400mb retina files become 220mb files. It works on both retina and non-retina MIBs, but you'll see a greater file size decrease on retina.

How to use it:

The MIB Optimizer tool comes preinstalled when you run the Designd Plugin installer from our download page (

  1. Open it.
  2. Drag a MIB onto it and hit start processing.
  3. Test the MIB on a device to make sure it didn't break anything.
  4. Marvel at your new smaller file size.
  5. Note: ( If your MIb is not functioning properly then please select the option of Android Compatible) then Optimize your MIB.( Please see the Screenshot at the end).


We've run literally hundreds of MIBs through this that are live in the App Store now, and we have yet to see it destroy a MIB, but ALWAYS test the MIBs you run through it before you publish to make sure you're happy with the resulting image quality.


If you're using PNGs to do things like rounded corners, there may not be enough transparent pixels for the optimizes to realize it should be a PNG, and it will convert it to a JPEG. In those instances, make the box 99% opaque and the optimizes will leave it alone.


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