Some of our features, like Email Photo, Fan Wall, and Voice Recording, require background images with a certain level of opacity in order for the text to be easily read over the image. This is very easy to design using Photoshop.
1. Once you have the image all set up and ready to go in Photoshop, select the opacity meter in the toolbar on the right hand side.
See here for more information on how to create an image in Photoshop.
2. Drag the Opacity level to around 20-40% depending upon how dark your image is. Also, make sure you have a solid white background layer!
3. After you're happy with the way your image looks go to File-> Save for Web Devices -> Save
This will ensure you save it as a .png file!
That's it! Now just upload the .png file into the Appearance step!