Summary. The default startup image for newer Apple computers is the galaxy desktop photo, even if you’ve changed your desktop image to something else. This page explains how to change the startup picture.
Solution. To select a different startup image, follow these steps.
- Navigate to the Hard Drive > System > Library > Core Services folder and find the DefaultDesktop.jpg file.
- Right click on the file (or control click) and choose to copy the file. Then right click (or control click) on the desktop and paste it there (Paste Item). This will be your backup of the file.
- Find a high quality image to replace it with. Choose a high resolution image that is equal to (or similar to) your computer’s maximum display resolution. For example, a PowerBook connected to a 24 inch display would have 1920 x 1200 resolution. A 5 megapixel photo or higher would be adequate.
- Once you’ve decided on a startup image, copy it, and then rename the copy to DefaultDesktop.jpg and move it to the Hard Drive > System > Library > Core Services folder. When asked if you would like to overwrite the existing file, choose yes. You may need to authenticate with your name and password to overwrite that file. For more information, read the Wikipedia page on video resolution.
When you restart your computer, the new image should be visible.