Excellent question. I need to make several videos on how-to-do stuff. For now:
1. Logon with your user id
2. In the user module on the right, click on 'user profile'
3. You should see your profile page. Top left area mouse over edit and a drop down will show you 'update your profile' and update your Image. Click profile option
4. You get three tabs, Portrait, Contact Info, and Forum Settings. Click Contact info
5. There are two fields, password and verify pw, put the new one in both fields.
6. Click update. ( I think it will refuse if the two do not match).