Touch UI Thumbnails

As far as the touch ui the only info I have about thumbnails is what i've reverse engineered from the geometrixx store (the docs were not helpful). I want to have these thumbnails in my package I do not want the user to have to upload/configure them.

In sites.html/content I have added thumbs in /content/my-store/jcr:content/image/file/jcr:content/dam:thumbnails and these show up correctly.

This seems like an awful place to have to put my thumbs so I assume its incorrect and I should be loading them from somewhere else?

With the same sites.html page if I dont have any thumbs configured it shows me a geometrixx homepage, is this the default? (If i go into /libs/wcm/core/content/sites/properties.html/content/my-store I get an error if i try to 'generate preview' would this affect which thumbnails is displayed).

I have aem commerce installed and configured for my store but when I go to /aem/catalogs.html/content/catalogs there is no image. The geometrixx catalog image url is /content/dam/geometrixx-outdoors/geometrixx-outdoors.thumb.319.319.png but even after copying that directory into the corresponding location in my-store and renaming it It still fails to display an image (even the wrong one).

How does aem decide to use this image url? (the one for my store is always empty i.e. no src attribute)