Nivo Slider 1.91 won't select images from media library

I’ve got Nivo for WP 1.91, went to replace one of the images in the slider from one I had in the media library, and Nivo won’t allow me to do it.

When I hit “select file”, the dialogue box only opens to the image folder on my computer, not the media library. Even so, it won’t select or upload from their either. Other than that, the slider works fine. I’ve tried it on both my macbook pro and my HP desktop, same result on both.

I’ve got 2 theories. 1: the plug in won’t allow me to upload as it is out of license, and this function will be restored if I purchase the latest version of Nivo for WP. 2: There is a glitch in my plug in that has to be fixed.

Would really appreciate opinions more expert than mine!