For Windows98, ME or Windows 2000, if you have View as Web Page enabled but do not see a picture preview in Explorer:

Start Regedit

Go to Registry key: HKEY_CLASSES_ROOT \ file type \ ShellEx \ {BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}
Make sure the Default Value "{7376D660-C583-11d0-A3A5-00C04FD706EC}"