Two questions on display_files_for_item()

I came across two problems when I applied this function:
First, if the item displayed has two images, this function will display all of them. However, I wanna just display one of them to represent the item.
Second, when I click on the image displayed, it will lead to the original image. I would like to show the item's metadata (Dublin Core page) instead of the original image.

Thank you for reading this.