Choose Size of Download

Given that Flickr generally makes six different sizes of an image available for download, might it be possible to do that via Viewfinder?

I understand that we can, already, search on the basis of minimum size and that we can then use some other application to reduce an image down to a suitable size, but that seems quite inefficient when Flickr already makes smaller sizes available. It would be useful if we could set our download size via the toolbar, separately from the Min. Size selection.