Unfortunately this is not possible, since you uploaded the files you should have a copy of it locally or from where you got it. As a work around you can get the files from the players that cached the resources that you use in your signage.
In XP
C:\Documents and Settings\USER_NAME\Application Data\SignagePlayer.XXX
(USER_NAME = logged on windows XP user)
In Windows 7 / Vista
C:\Users\USER_NAME\AppData\Roaming\SignagePlayer.XXX
To get to this folder, Click on Start, and on the search field type %appdata% hit enter, and in the SignagePlayer.xxxx folder.