how to change the adafruit 132x64 oled splash screen?

so I would really like to try and make my own splash screen, I've tried and failed because all of the tutorials are on an older version of the library and they have changed it so that the splash screen is a second document called "splash.h" I tried changing the hex code to my own image but when I loaded up the code it didn't display the image, just a bunch of lines when started then went to normal. I really have no idea how to do this and if someone could help me that would be great!