Once you reach level 85 and have at least 1.000 collected pictures in your scrapbook, the Real Holy Grail can be found by searching for gems. The Grail is activated by dragging and dropping it onto your profile picture. With a solemn animation, the game confirms the activation.
From now on, it will be much easier for you to discover missing items from your scrapbook in the hall of fame: While items already found are not highlighted, missing items will literally pulsate. This is the indicator that the "flashing" item is still missing in your scrapbook.