SFML C++ How to color sprites with 12 different colors

So, I am trying to create a Warcraft II RTS clone with SFML. I finished my menu now, a menu which should support 12 different player thus 12 different colors, however I have problems with colorizing the different sprites i downloaded from the internet, and probably making 12 different png files to load for each unit/building would be a huge waste of time and memory.So, I am trying to create a Warcraft II RTS clo