[Android Themes] PiousInquisitor:
Required programs:

Vector editing program such as Inkscape, Libre Office (Open Office) Draw, or Illistrator. For this tutorial I will use Inkscape.

Simple text editor. Dont use a word processing program like word. Note pad or gedit work fine.

Step 1. Open to the xml you want to view. They are usually in /res/drawables. For example: ic_qs_wifi_disabled.xml

<?xml version="1.0" encoding="utf-8"?>
<vector android:height="29.5dip" android:width="32.0dip" android:viewportWidth="26.0" android:viewportHeight="24.0"
xmlns:android="http://schemas.android.com/apk/res/android">
<path android:fillColor="#4dffffff" android:pathData="M17.500000,16.500000L5.800000,3.400000c0.000000,0.000000 0.000000,0.000000 0.000000,0.000000l-2.700000,-3.000000L1.600000,1.800000l2.200000,2.500000c-2.000000,1.000000 -3.200000,2.000000 -3.400000,2.200000L13.000000,22.000000l0.000000,0.000000l0.000000,0.000000l0.000000,0.000000l0.000000,0.000000l3.200000,-3.900000l2.400000,2.700000l1.500000,-1.400000L17.500000,16.500000L17.500000,16.500000z" />
<path android:fillColor="#4dffffff" android:pathData="M25.600000,6.500000C25.100000,6.100000 20.299999,2.100000 13.000000,2.100000c-1.900000,0.000000 -3.600000,0.300000 -5.200000,0.700000L18.700001,15.000000L25.600000,6.500000z" />
</vector>

Step 2. Create a new text file with the same name but with the svg extension. ic_qs_wifi_disabled.svg. Then paste the following into the file:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>

<svg height="210" width="400">
<path d="pathData goes here"
</svg>

Step 3. You need to change the size of the image. Observe the portion of the xml that says android:viewportWidth and android:viewportHeight. Paste the values into the svg.

<?xml version="1.0" encoding="UTF-8" standalone="no"?>

<svg height="24" width="26">
<path d="pathData goes here"
</svg>

Step 4. Now you need to copy over the path data from the xml. Look for android:pathData in the xml file, the string following this needs to be copied to the svg file you created.

M17.500000,16.500000L5.800000,3.400000c0.000000,0.000000 0.000000,0.000000 0.000000,0.000000l-2.700000,-3.000000L1.600000,1.800000l2.200000,2.500000c-2.000000,1.000000 -3.200000,2.000000 -3.400000,2.200000L13.000000,22.000000l0.000000,0.000000l0.000000,0.000000l0.000000,0.000000l0.000000,0.000000l3.200000,-3.900000l2.400000,2.700000l1.500000,-1.400000L17.500000,16.500000L17.500000,16.500000z

Paste it where it says pathData goes here.

<?xml version="1.0" encoding="UTF-8" standalone="no"?>

<svg height="24" width="26">
<path d="M17.500000,16.500000L5.800000,3.400000c0.000000,0.000000 0.000000,0.000000 0.000000,0.000000l-2.700000,-3.000000L1.600000,1.800000l2.200000,2.500000c-2.000000,1.000000 -3.200000,2.000000 -3.400000,2.200000L13.000000,22.000000l0.000000,0.000000l0.000000,0.000000l0.000000,0.000000l0.000000,0.000000l3.200000,-3.900000l2.400000,2.700000l1.500000,-1.400000L17.500000,16.500000L17.500000,16.500000z"
</svg>

Note that this particular xml has two sets of android:pathData. You need to also include this in your svg below the first set of data.

<?xml version="1.0" encoding="UTF-8" standalone="no"?>

<svg height="24" width="26">
<path d="M17.500000,16.500000L5.800000,3.400000c0.000000,0.000000 0.000000,0.000000 0.000000,0.000000l-2.700000,-3.000000L1.600000,1.800000l2.200000,2.500000c-2.000000,1.000000 -3.200000,2.000000 -3.400000,2.200000L13.000000,22.000000l0.000000,0.000000l0.000000,0.000000l0.000000,0.000000l0.000000,0.000000l3.200000,-3.900000l2.400000,2.700000l1.500000,-1.400000L17.500000,16.500000L17.500000,16.500000z"
<path d="M25.600000,6.500000C25.100000,6.100000 20.299999,2.100000 13.000000,2.100000c-1.900000,0.000000 -3.600000,0.300000 -5.200000,0.700000L18.700001,15.000000L25.600000,6.500000z"
</svg>

Step 5. Save svg, open then export as a png. Save the svg file then open it with Inkscape. Now you can edit or export the image as a png. To export select File > Export Bitmap. Enter the parameters you wish to use and then hit Export. Be sure to select the path you want to export to.

Let me know if you need any help.

Speaking of batch processing check out my tut on G+: https://plus.google.com/117284285211384809323/posts/j6ZTCVkNEuZ