The image is indeed listed in various places as Royal Marines at Tel-El-Kefir, problem is I don't think there were any Royal Marines at that battle.
Mad orc's painting has been pinned so many times the variously incorrect IDs have self-proliferated. Until that painting can be properly attributed it will have to go into the 'online FUBAR' basket.
It does however seem to depict a late Victorian battle against a foe in Islamic costume. Not much outside of the Egyptian or Ethiopian actions really fit that bill. I think it is likely the battle is Tel-El-Kebir with the regiment wrongly identified as Marines.