I was under the impression that the way to create tab bar icons is to create the icons with the appropriate transparency (after reading this http://greenerpastures.dk/blog/iphone-udvikling/how-to-make-tab-bar-icons). I've changed my tab bar to be gray so my icon is in the range of gray to white depending on the transparency. Here's and image with no transparency in the icon image:
And here's one with quite a bit of transparency in the icon image:
My question is, how can I make it so my icon is black while keeping my tab bar as gray? Should I just use a regular image and forget the transparent icons? Is it bad practice to use non-transparent images?