transparent sprite background
**Is your feature request related to a problem? Please describe.**
when I used my background color other than black, I found my sprite in a box where its background is black and that is really annoying, I want a transparent background feature,

**Describe the solution you'd like**
In img() function, add a new keyword to the transparent background where 1 describe True for a transparent background and 0 describe False, and describe background as black

Thank You!