Drag & Drop (or even Open dialog) user-selectable image

I have a PDF with a spot I'd like a user to be able to place their own
image in the field. JPEG would be fine.

I've only been able to find 2 answers:

1. It's a JavaScript that only works inside Acrobat that can dynamically
change the icon on a button; doesn't work in Adobe Reader.

2. Insert a ton of images in invisible fields and have them appear when a
particular button is pushed.

Neither of those do what I need it to do. Is there some sort of
JavaScript I can use that'll open a dialog box, allow the user to select an
image, then place that image in a field/button icon from inside Adobe
Reader and/or Apple Preview?

Thanks.