after migrating to D7 all images are missing After migrating to D 7.20 all my images are gone, actually they exist on the server but are not being displayed at all. I have a multi-site installation and I've successfully migrated all the content and re-enabled the modules. 
I have a page where all the users pictures should be displayed and none of them are being displayed. So, I've created a new account and uploaded a picture for it and this new picture appears. What should I be looking at? How can I migrate all the pictures to the new installation properly ?

Thanks.
The storage of user pictures changed from D6 to D7. I think the answer for your problem might be found at Picture Migration on drupal.org.