Patterns not showing

Trying to figure out why the thumbnail for my patterns isn't showing When I select them they show up on the item so they are uploaded correctly.

Also trying to figure out what size/dpi might be required for patterns to show proportions correctly. For instance, this pattern is 12x12in (close to the width of a shirt) 

but if I were to select it for a text that spans the width, it only shows a very small portion unless I make the text extremely large (running off the shirt), and it still doesn't show proportionally correct. I am guessing there is a measurement setting I am missing somewhere maybe?