remove the pic from the list after it's been picked, i guess. if i did it, i would have had a function that generates a series of such images picked from a common gallery rather than generating each picture in the document.  then again, i probably would have also done it server-side and done a number of other things differently too.

the only thing changed between the op version and that version is the spacing is different. so do what I said to do. each time a pic is placed on the page, remove it from the list of options. or if you want a different solution, write a function that picks x random images from a list by shuffling it and then iterating through. neither of these are fast solutions for the general case, but they're easy to implement and will not cause performance problems on small lists.