Return to Original Image Size

So I just upgraded to 2.6.1 and I saw that ALL my images were changed from 550px width to 500px. This happened on all my posts going back over a year.

I have read about people making changes to the template’s function.php as well as includes/media.php, but neither changed my old images back. When I go in Firefox to view them by themselves I can see that they are still at 550px, which means WP is changing them via the html.

Also, if I go into the advanced image editor change the file to the original size and then save, everything is back to normal. But this takes forever to do manually.

Any ideas? THANKS!