Captivate 9, Image Buttons image file won't load in

I'm trying to load an image that I made in Illustrator in to use as one of my buttons, the file format is .png, but when I go to make the button an image button and select the folder symbol next to it to load in an image, I will select my image then click okay and then nothing happens. I've loaded in one image this way and it worked, it shows up in the little gallery underneath this section now. So I thought to add the images I want to use to the gallery folder directly, within the captivate folders, but I did that and they are not appearing in my gallery either.

I would simply like to use images I have made as button symbols, is there something that could be preventing this function from working? Like I said, it worked fine for me once before. Thanks!