Probably nothing to do with Drop Box...but we use Drop Box and also File upload for adding a File (image) to add to our Item(s).
Some of our Items have multiple Files (images) in sequence (ex. pg1, pg2, pg3) etc.
We would like the thumbnail to display the first image, not the last one.
We tried using Drop Box, not using Drop Box (file upload), reording, renaming (alphabetizing) etc.
Pondering the code for the div class <div class="item-img"> to try to understand why it wants to choose the last File (image) for the Item thumbnail.
...nothing seems obvious.
We would appreciate if someone could guide us towards an area of the code which might affect this behavior.