I would like to make a widget that will render the HTML for an image slider. Its main property needs to be a set of images that the designer selects, ideally from the media library. It could alternatively be a set of image uploads (with no limit to the number of images uploaded), or at worst, a folder in the content tree that contains the images to be used.

I can't find any multiple-file-selection form controls built-in, so it looks like I'm going to have to roll my own form control. It would be nice to reuse the web part that lets you select a single file from the media library. However, the more I dig into this, the deeper the rabbit hole goes.

Does anyone have experience building a multiple-file-selector form control? I'm surprised there's not something publicly available. Any advice or leads would be much appreciated.

Bryan