The White Lums appear in the Game Boy Color version of Rayman 2. If Rayman dies in a level after having collected a White Lum, he will re-spawn at the point where he took it. Their function is exactly the same as the Green Lums in the other versions of the game and as the Photographer in the original game. It is unknown why they were changed to being white in color.
In the Game Boy Advance version of Rayman 3, White Lums are known as Silver Lums and they grant Rayman an additional life; in this, they serve the same purpose as the life statues in the original game and the Game Boy Advance version of Rayman Raving Rabbids and the Super Red Lums in the Game Boy Color version of Rayman 2. Unlike life statues, it is possible to collect them again upon replaying the level in which they appeared. This is mainly due to them being the only source of lives in the game, unlike the the original game where collecting 100 Tings and completing a bonus level would also grant an extra life.