Accessing a .DROID files, how do I rip it, and possibly mod it's image files?

[Morgenni]

Hello, I'm someone who likes to mod games, now it's time to step up, I am trying to mod the .DROID file from a game named "Gold Mountain", but I could not extract the images from it, how do I do it?

I've tried using HxD to try and extract the images, but failed, I'm also looking out to replace it with another image file.