Yes that icon...
It must be somewhere, since I see it even when offline.
My iPhone is jailbroken, but I can't seem to find the place... :-(
Try this path...... /Library/Themes/THEME/Icons/. Have the prefered icon named exactly the same way it is on your iphone. Let me know if this works.
EDIT: Better still try this... found it on ilounge
You will need the following:
* Jailbreak iPhone/iPod-touch.
* SSH Server installed on your iPhone/iPod-touch.
* WinSCP if you're on Windows.
Lets get started:
1. Start the Wifi on your iPhone/iPod.
2. Start the SSH server on your iPhone/iPod.
3. Check IP address your iPhone/iPod was assigned with: Settings -> Wi-Fi -> (the relavent blue arrow) -> IP Address.
4. Connect your iPhone/iPod with WinSCP, using the the IP address we checked and the following user information: Username:root Password:alpine
(I'm not sure what is the root password on iPod-touch, it could be dottie)
5. Navigate to the webclips directory: /private/var/mobile/Library/WebClips/
6. You will see directories similar to this one: 833C7AC6-9AD4-4350-A873-6CE648B76AF4.webclip
Each of these directories contain two files: Info.plist and icon.png
7. Move through the directories opening the Info.plist file until you find the webclip you're looking for.
You can now alter the webclip information by editing the Info.plist file, which is nothing more than a XML file.
8. If you have a better icon you can simply replace the icon.png file.
9. You're done. Now reload the SpringBoard, by either reloading your iPhone/iPod or use a 3rd party app.