When you are inserting the image, just click “image” down the bottom of the link to option. This will link to the image not the generated page for that image.
So for instance if that is the HTML which inserts the image, in which area would I insert the ‘file’ tag?
Also this is rather irritating because when I first installed the wordpress it automatically linked to the High res file as the default option, but now the plug in has somehow changed that and need manual editing?