Collectible Card Game Headquarters

This might just be a "me" problem or something I've done wrong, but I can't figure out how to fix it. Hover images of cards don't work, and even though Xmage says they're downloaded and I can see them in the file location, images of all mana symbols and tap symbols and such are broken as well.
I tried to add pictures, but I got the message "your post looks too spammy for a new user."

Did you download the symbols by using the menu "Symbols" in the top bar?

Yes, and they work when the program generates card images on the battlefield and in hand, just not when hovering or requiring costs.

It's as though it can't find the images when cards are hovered over. It shows the little "image not loaded" box, and the location of the image in text in parentheses.