Ensure that the image has not been resized and it is saved to your C: drive (hard disk) or other local drive on the Exchange server. This is required because the disclaiming service runs under a different user account which does not have access to your mapped network drives. In addition, you must ensure that the “NETWORK SERVICE” user account has at least “Read” permissions to the image.

If you have imported your template into Signature Manager Exchange Edition and you cannot see the logo, make sure that it is also on the C: drive. If you import your template without saving it to a folder on your C: drive, your server won't find the image.

We also recommend that you use web-based images instead of embedded local images as they are more reliable.
Mail Disclaimers Signature Manager Exchange Edition Troubleshooting