Hi,
As we have template override and language override, do we have any overrides for helper files. I want to customize the below file:
administrator/components/com_virtuemart/helpers/image.php
Changes in core file function should be made by writing a plugin. Like overrides, custom plugins do not get overwritten during updates. Some info on http://docs.virtuemart.net/component/flexicontent/34-development/84-extension-plugins.html