Creating Witcher 3 mod. My own pictures on paintings

[xxfaalcoonxx]

So I want to create my first mod in which I will replace all paintings in Witcher to my own images. For example to put them later on the walls in Corvo Bianco. But there is a problem I don't know where and with which to start. Can someone help me with this? I was trying with Modkit and Mod Kitchen. I uncooked my Witcher files but I didn't know which ones are for paintings. There was too many of them and I got lost. I think creating that kind of mod would be easy. It is just replacing the textures to my images. But as I said. I don't know how to do that. Thanks in advance for any help and tips.