@sharonyue No, I don't think so. It's unusual for avatar images to have transparent backgrounds 🙂
@Joenel-de-Asis172 That is actually the best way to do it.
The other way would be to remove that html from the profile template in your theme. However, unless you are making your own custom theme, your changes may get overwritten when the theme updates.
So CSS is the way to go.