Motorola Droid :: Metamorph - Editing .png - Change Colors Of Wif Bars

I would like to change the colors of the Wif bars on the status bar at top of screen I extracted the .png files (blue bars), opened them in Paint, and manually changed the color to yellow. Zipped them back up in Metamorph format and pushed them to my Metamorph format and pushed them to my sdcard Applied theme using Metamorph, and it worked, except that the background is now white. I created a theme using the original 5 files. I created a theme using the original 5 png's with blue bars, applied the theme, and it worked and it doesn't have the white background. I think I understand what's happening, but not sure how to format the pictures correctly so just the bars show without the background. Any help appreciated, thanks