The slide effect is disabled for technical reasons on Internet Explorer 8 and lower. It gets substituted by the simple fade animation. If you still prefer sliding, try the Captions tab > Caption style setting's Mixed option. It'll slide only the bottom part of the caption, while the top half will remain visible.
Special effects, such as desaturation are created on the fly, without server resources. This means the browser needs some time to apply the effect on the thumbnails. It's often very fast and causes no noticeable delay on modern devices and browsers. However, when you resize the window or change the device orientation, the special effect [...]