Cool idea, would require a lot of additional sprites though as you'd need an extra 15 new sprite images just to show a ruby amulet as being red? Whilst I appreciate the little touches, I don't think it's that important. I would rather see the effort spent on the character customisation options. Additional hairstyles, beards, coloured clothes etc.
No, the way sprites work anything greyscale is set to the color you put in the files. An example is every partyhat ingame has the same sprite, just different colors. So the necklace thing WILL require a second set for things like holy and unholy symbol, ammy of lucien, and armadyl pendant. The only change to get all the colors right would be to set a gem color in the script.
Unless I totally screwed up and used a wrong shade for the gem, which I'll test tomorrow x3
You are correct in needing extra sprites, I wanna talk to Mod Kleio about that since he was responsible for all the skill capes which each required a set of sprites. I'm not sure how time consuming that is with this server since I havent been active much in years... so much has changed lol
Now I want to create some new hair styles. OMG a Viking braided beard hahah
Far as clothing color, that should be simple since they all use the same sprite, just need different colors added to the rotation, the head sprites would be the only thing needing sprite changes, but that's a fantastic idea.