I don’t really see the need to use 32 million colours just because i can. I find I play around with colours then come back to white.
It’s somewhat ironic to be having this conversation on a site where it’s all about the white black and grey.
As to the gallery, it’s a plugin from https://qdig.sourceforge.net, I wrestled with it a bit but it’s all there. The developer is very thorough with his support to.