Mobile device software developer Vorino Software has posted a useful tutorial on how to make your own wallpaper for your BlackBerry Home Screen.

Here's how to do this from a Web image:

1. Browse the web page with your BlackBerry using the Browser application.
2. Choose the Select Mode menu item.
3. Select the image by scrolling with the wheel.
4. Select the Save Image menu item. 
5. Select the Save button and press Return (or click wheel).
6. Escape (or Close) out of Browser.
7. Start the Pictures app, scroll to your new image, then select the Set As Home Screen Image menu item.
8. Escape (or Close) out of the Pictures app.

Verino offers several free, sample wallpapers where you can test this process out. Here's one for BlackBerry 8700c's 320x240 resolution:

The procedure is also easy from an e-mail attachment. Here's what Verino recommends:

1. Open the Messages app.
2. (Optional step, to quicken menu selection) Scroll to highlight [1 Attachment].
3. Select the Open Attachment menu item.
4. Scroll down to Full Content.
5. Select the Retrieve menu item.
6. Select the Save menu item.
7. Select the Save button and press Return (or click wheel), and again for the OK button.
8. Escape (or Close) out of Messages.
9. Start the Pictures app, scroll to your new image, then select the Set As Home Screen Image menu item.
10. Escape (or Close) out of the Pictures app.