Android :: PNG Optimization On Packaging Process

I've noticed that the PNGs of my application with some gradients effects looked terribly bad at the device (a Samsung Galaxy) and at the emulator, and I've found the following note at the documentation (http://developer.android.com/guide/topics/graphics/2d- graphics.html):

Image resources placed in res/drawable/ may be automatically optimized with lossless image compression by the aapt tool. For example, a true-color PNG that does not require more than 256 colors may be converted to an 8-bit PNG with a color palette. This will result in an image of equal quality but which requires less memory. So be aware that the image binaries placed in this directory can change during the build. If you plan on reading an image as a bit stream in order to convert it to a bitmap, put your images in the res/raw/ folder instead, where they will not be optimized."

I've tried the res/raw suggestion, but it didn't worked.

I've tried to use the image as JPEG as a workaround, but I couldn't use 9-patch.

I've uploaded a comparison between the original png and the "optimized" png that is shown on the emulator or devices: [url]

One workaround would be put the images at /assets/ and manually load and set the image on the ImageViews, but it requires a lot of code changes.