If you mean once per browser session, simply set cookieForFirstLight to true as shown here in the Configuration section of the lightbox.js file for this version (starts around line #47):
Code:
// -----------------------------------------------------------------------------------
LightboxOptions = Object.extend({
//
// Configuration
//
fileLoadingImage: 'images/loading.gif',
fileBottomNavCloseImage: 'images/closelabel.gif',
cookieForFirstLight: true, // use session only cookie for first light? (true/false)
overlayOpacity: 0.8, // controls transparency of shadow overlay
animate: true, // toggles resizing animations
resizeSpeed: 7, // controls the speed of the image resizing animations (1=slowest and 10=fastest)
borderSize: 10, // if you adjust the padding in the CSS, you will need to update this variable
forceLocal: false, // set to true to force lightbox into a frame or iframe
// (default: false) - will allow lighbox effect to appear on the top page of an iframe if any
startCallback: function(){}, // callback for ligthbox start
startCallbackType: 'afterFinish', // scriptaculous effect callback method default = 'afterFinish'
endCallback: function(){}, // callback for lightbox end
endCallbackType: 'afterFinish', // scriptaculous effect callback method default = 'afterFinish'
// When grouping images this is used to write: Image # of #.
// Change it for non-english localization
labelImage: "Image",
labelOf: "of"
// End Configuration -----------------------------------------------------------------------------------
Bookmarks