[CentOS] Icon .png file loading error after graphics driver upgrade

Dear,

I updated my nvidia graphics driver on one of the CentOS boxes.

When I log in my account, icons are not displayed correctly.
They are displayed as small empty squares, and there are error messages like
"Fater error: failed to load <file name>.png : version error" for each icon.

If I log in as super user, everything is OK.  Icons are OK. No error messages.
Do you have any idea?

Thank you.

-john