Tabbar icons issue

My appli开发者_如何学Gocation is a tab bar based app, I have 5 tabs each of which requires to have a customized image for the icon. I tried loading the image for each of the tabs, and it works. The problem is I see a greyish circle for one of the icons, instead of a football image. Each of these images are in .png i.e transparent. The football art is basically black & white like any football, the image loads but I see a circle that has a solid grey color. I tried extracting the image from the PSD several times. I am not sure if I need to tweak images in the interface builder or photoshop? please help. Thanks

Toolbar and tab bar icons are created just from the alpha channel of an image. If you want to provide different shades of grey, your image file must contain these shades in the alpha channel (i.e., set the opacity of the pixels to something between 0% and 100%).