public static AssetManager newAssetManager(URL configFile) {
        checkDelegate();
        return systemDelegate.newAssetManager(configFile);
    }
Compresses a raw image into a stream.

The encoding is performed via system libraries. On desktop, the encoding
is performed via ImageIO, whereas on Android, is done via the 
Bitmap class.

@param outStream The stream where to write the image data.
@param format The format to use, either "png" or "jpg".
@param imageData The image data in {@link com.jme3.texture.Image.Format#RGBA8} format.
@param width The width of the image.
@param height The height of the image.
@throws IOException If outStream throws an exception while writing.
jme3-core/src/main/java/com/jme3/system/JmeSystem.java