I found a way to change the theme of Skype. In C:\Program Files (x86)\Skype\Phone there is a file called SkypeResources.dll
This has all files and buttons which someone could replace with any image editing tool.
Not sure why i'm posting this but if anyone does this hit me up
Just use some sort of save data back up tool, and then find where it got backed up on your SD, from there, just select the back upped file with tool and change the stuff.
After that load the back up, and you should have all the data.
I find this the best and most useful answer.
Anyone reading this thread, I highly recommend doing this method, because its just better than using MinGW (it works temp, but not big edits/as free as linux).