Example of how to declare in php:
Array
(
[0] => http://i.vimeocdn.com/video/637696211_200x150.jpg
[1] => http://i.vimeocdn.com/video/637696227_200x150.jpg
[2] => http://i.vimeocdn.com/video/637696217_200x150.jpg
[3] => http://i.vimeocdn.com/video/637696211_200x150.jpg
)