I have inserted an image that points to a media graphic. When I update that media object, the rendered page fails to show the new graphic.

For example:
/media/site assets/homepageproductgraphic contains a reference to a product.jpg

I update product.jpg in gimp and save. I confirm the file is updated.

I then go to:
/media/site assets/homepageproductgraphic

and click on [ choose file ] and select the new file. The thumbnail confirms the new graphic

I then click the [ save ] "floppy" icon.

I click away and come back -- the thumbnail looks correct.

However, on the rendered home page, the graphic has not changed. I empty the browsers cache, still no change.

Where do I start to look to address this?