If you know how to to do this in Javascript you should probably be able to do it in Skuid.  You need to drag an arbitrary field into your page and then in the fields renderer properties select “custom renderer”   Select a name there.  Then go to resources tab and create a Javascript resource of type “Inline Snippet”   Here is where you put your javascript to create a fake lookup to the items in your documents folder. 

We would reccomend however that you store these images as attachments and that you use the Skuid File component to look up to attachments.  This would allow you to satisfy your requirements declaratively.