Hi Mohd Rafie,
1.Sorry I'm not very technical, I dont know what shortcodes I'm using. I didn't do anything but download the plug in and use the thickbox setting.
2.Yes I did regenerate the thumbnails, they got smaller but they are still overlapping. They are worse when the images are larget.
I've just deactivated the plug in.
http://sugaredsaffron.co.uk/colouful-50s-styled-wedding-shoot-london-wedding-suppliers/