How do I make sprites better

So I just downloaded the free version of Scirra and I was going to make a game (platformer) by copying and pasting Mega Man sprites onto the project (I will cite) and there is a white background with these sprites, is there any way to get rid of that without having to manually erase all the white? Can I use "fill" to erase? Thanks in advance.

-Your everyday programmer

So, I found how to do it, for anyone else with this problem, here is how to fix it:

Open sprite editor

Click fill

Turn all values (Red, Yellow, Blue, ALPHA too, ect.) to 0

click on the white areas