Go to your portal URL (usually something like yourcomanyname.imagerelay.com)
Click on Forgot Password on the login screen.

Enter your username on the next screen.

A reset password link will be sent to your registered email address.
If you do not know your username you can reach out to us directly at support@imagerelay.com and we can look it up for you. Or start a conversation with our Support staff using the intercom bubble at bottom right of this screen.
Further Reading:
Changing Your Password