user interface

Its a GIF or a video, i wanna replace it with an image cause it lags pc most of the time if someone could help I am not the owner of the Server. 1.7.6 server

Hi everyone, I would like to learn about the UI editing and customization process in PW clients. First of all, I have a basic question: Are surfaces.pck and interfaces.pck files "protected" and shouldn't be edited, or is it perfectly fine to modify the aesthetics of your PW private server user...