No boot screen editing in Mint?
 

I am new to Mint, but coming from Ubuntu.

I have used Ubuntu for my desktops for awhile, but I have anew laptop which doesn't want to play nice with Ubuntu. I tried Mint and found it to be extremely compatible with the machine.

So far so good. I'm working on doing some of the things I had set up with my desktops. However, I can't for the life of me figure out how to replace the MintOS boot-up screen with one of my own.

The software manager allows me to download Usplash appplications/ thems, but they then don't work AT ALL.

I'm running 32bit Mint, with a GNOME desktop.
Any helpful suggestions?

Can you explain more in detail what is happening with the themes, and how they are not working?

If you have the most recent Linux Mint using Grub2 you may need to install grub2-splashimages.
Try: sudo aptitude install grub2-splashimages

Then go to the /etc/grub.d/05_debian_theme file.
There is a line which begins with WALLPAPER, comment it out and enter a new line with the path to the image you want then run
sudo update-grub

Works on Ubuntu, haven't tried it on Mint but if you have Grub2, it should work.