With RPG Maker XP & Vx ace there was an added to
show pictures additives and substractives.

In Rpg maker 2003 with dynrpg there's a plugin that support it:
https://rpgmaker.net/engines/rt2k3/utilities/11/

Actual comparison of a light in player using alpha channel (that looks like similar to the own rpg maker pictures with transparency) and additive light of blending plugin with dynrpg