To change the Beginning Trainer, go to User Cp, and click Edit Profile Info. Then, there should be a section labeled "Custom UserTitle" or something like that, and type in what you want there. Be sure to hit "Save Changes" at the bottom.
Like the other said, save as png. From what I can see, they aren't bad for recolors. The Charmander thing is good, but the thing on its head doesn't look very natural. Try to blend it more.
To save as png, when you're saving your sprite, there's a drop-down menu with a blue arrow on the end. Choose png from the list that comes up.