problem viewing pics in gallery

[tilly41]

Have just started building my website and being a novice I am learning as I go along. I have created galleries and all was fine. Clicked on pics, they came up centered etc, worked great. Now however when you click on a pic it comes up much bigger and on the left ( looks odd) when you click again to close, it closes the whole page and gallery. If you wait a couple of minutes it does work correctly but then it happens again with the next pic. It seems to be slow loading each time. Its not my pc, I have logged on on 4 different computers and it happened on them too. Can anyone help me please??