Using Javascript to upload an image to PDF forum, and then some.

Currently using Java Script in a PDF forum button,

    event.target.buttonImportIcon();

It works but there are some issues.

1. The files all show up as idle even though I can upload them.
2. The default file format is PDF, I want it to be JPG
3. I only want JPG's and PNG's to be allowed.

Does anyone know any JS or have any other suggestions that may address these issues?

Any and all help is appreciated.

Running the most current version of Acrobat on Mavricks.