To prevent this from happening with every update you would need to make a copy of the graphite theme you edited and rename it as your custom theme then go to the admin panel and upload it. Make sure you have zipped your new theme folder before uploading it. Remember to update the theme.xml and the theme images so you can easily locate your theme. Never delete the graphite theme.
but now I noticed new problem, site formating is gone. page width only about 824px and all pictures and fonts are resized (smaller)
I have reuploaded the theme , reinstalled, nothing. all themes now 824px. any ideas