Having trouble creating a super banner? Here's how in 10 easy steps:

1. Open the image. 
2. Click on the Crop tool.  
3. Enter the height, width and resolution you want in the tool bar. (400, 800, 72) 
4. Drag the cursor over your image to select the portion you want. 
5. Press "Enter" (or "Return") on your keyboard. 
6. Select "Save for Web and Devices" from the File menu. 
7. Set the type to "JPEG" and the quality to "Maximum" 
8. Make sure "Convert to sRGB" is checked. On a Mac, check "Embed Color Profile"; on Windows, I think this is called "Embed ICC Profile." 
9. Click "Save."  
10. Enter a new name and click "Save."