v1.5.5f IH 5.1.5

Problem: Images are not showing up in Google images

Cause: images in sitemap/sitemapproducts have a _LRG suffix in the url which renders to 404 not found error

I have balanced the admin/configuration/images settings with this site to another same version site which does not have this issue but it has made no difference - changing images/suffix for large images from default of _LRG to 'blank' does nothing either.

So needless to say I would be grateful for a solution. (i.e. have sitemap not include any suffix)
cheers,
Mike