WFM on WinXP 2003053108.
As Phil suggested: Edit > Preferences > Advanced > Scripts&Plugins "Allow scripts to change images" was not checked. Actually, none of the boxes were checked. Should they be checked by default? Perhaps my profile has been around for too many versions.
Nothing in Mozilla was broken or fixed.
-> WORKSFORME as per comments.
Just to clarify. This was NOT a bug. The problem was: Edit > Preferences > Advanced > Scripts&Plugins "Allow scripts to change images" was not checked. Sorry for the inconvenience. Rob