1. open x32dbg
2. open robloxstudiobeta
3. right click -> search for -> all modules -> string references
4. Patience
5. search for "splash", you will see something like :/images/RobloxStudioSplash.png
6. double click that
7. right click that in CPU, follow in dump, robloxstudiobeta_(stuff)
8. look at the dump window right below CPU, you will see the same :/images string
9. drag click all over the string until the green dot, make sure you don't select the green dot
10. press Ctrl+E
11. click "Keep Size" in the bottom left corner
12. now, assuming you have placed your splash in Content, change this to:
Content/RobloxStudioSplash.png (it doesn't have to be named RobloxStudioSplash.png, but i would use .png and name it something similar)
13. click "OK"
14. press Ctrl+P
15. click "Patch File"
16. name it anything, make sure the file extension is *.exe
17. if you have done it correctly, you'll see the new splash when launching.