Need change images
if (_config.GUI.Image == "https://i.imgur.com/CyF0QNV.png"
|| _config.GUI.Image == "https://i.imgur.com/T6orn2Q.png")
{

I think there's been a misunderstanding. I no longer host images for server owners, because the free image hosting sites like to take down high traffic images that don't generate ad revenue. If I provide server owners an image URL, it will inevitably get taken down due to high traffic, and will affect countless servers that chose to use it.

Server owners can get the images off the GitHub repo and host them on their own, or you can use the skin ID that the plugin provides by default.

can you provide GitHub repos?

It's on the plugin page sidebar