Do you get no change or any difference on mobile devices? Does the same lightbox appear on both desktops and mobile devices, despite having set them differently? Most likely the desktop version got cached and it's getting served to mobile devices as well. A separate cache can be set up just for mobile devices. This [...]
It's because you are running low on memory (RAM) of the device. The newer models don't seem to have this problem. The memory usage increases with the amount, size (and quality) of the images and the number of elements on the page (captions, special effects, overlay, borders etc). In other words, use the most minimal design [...]
While JIG itself is responsive, your theme might not be. You need a responsive theme to allow resizing JIG on the fly. If your desired content area is a fixed width container or has certain minimum or maximum CSS width limits then JIG can not cross those.
If you believe your theme is responsive, but still [...]