Buttons describe the images they show as "image", "GIF image", or "loading GIF". Hovering changes the button to say it's "Preparing to show image". Then the button fades out over three seconds, so that you don't accidentally reveal a gross image just by scrolling over it. Finally, the image is revealed. To hide the image again, just move your mouse.

Now fixed to handle the blurred image upgrade. Images are never blurred with this style, but you can click an image to keep it visible if blurred images are enabled.