the images for the front page for sliding and banners are all disappeared

I am using the Shop Isle theme.
For the front page (kpopkstyle.com), I have 5 images for the sliding section, and 3 images for the banner section. If you try to see the background images for them, the link shows error messages. I tried to upload those images again to update the front page, but it does not allow me to customize these sections even though i still have my original image files in the Media section.

I suspect that this happened after i tried to activate a plugin, but immediately deactivated and deleted it. It was a Content View plugin, but i did not create anything from this plugin before deactivating it, because it was not a right plugin for me.

All the images other than frontpage seems to work fine. Please help.

The page I need help with: [log in to see the link]