How to make sprites with ms paint?

Hello, I am new to the unity software and i am having a little trouble with adding sprites and a character sprite sheet. I dont know how to use photoshop so i have to us ms paint. my problem is i make the landscape and character and send it to unity 4.5 and it shows up but the sprite editor will not slice the the single sprites. i have the texture type set to sprite, the sprite mode set to multiple, the filter mode set to point and the sprite editor set to automatic. I looked on line but i couldnt come up with nothing and even if i manualy slice it my self. the white background of the image slices with the sprite. Please help and thank you (ps I have unity 4.5.2)

The problem might be the alpha channel. Edit the sprite with GIMP or some other tool to delete the white space around the character.

Paint doesn’t allow for alpha, it always leaves a white background where you didn’t draw. Like somebody else said, use Gimp, or if you have it, Photoshop. Just make sure you have a transparent background and save it as a PNG or another type that allows for alpha, as far as I’m aware JPG doesn’t allow an alpha channel.

EDIT:
The reason I’m bringing this up is the slice tool in Unity checks for the bounds of an area of an image. For example, if you had a picture which had 4 cubes on it in color, and you had an alpha channel, it would ignore the alpha channel and pick up on the 4 cubes.

Thats why spritesheets normally come with a solid color background, easier to delete the background.