Update README.md

Added screenshots

Author: reshmaharidhas

README.md

@@ -13,3 +13,13 @@ Built using Tkinter
 For bugs, questions and discussions, please use the <a href="https://github.com/reshmaharidhas/BMI-Calculator-python/issues">GitHub issues</a>
 
 ## Screenshots
+
+![image](https://github.com/reshmaharidhas/BMI-Calculator-python/assets/37250413/0cd5cf99-37df-4d73-81d9-aac0a43fcf98)
+![image](https://github.com/reshmaharidhas/BMI-Calculator-python/assets/37250413/46e8b324-5aee-49cd-ad0b-6670f165fade)
+![image](https://github.com/reshmaharidhas/BMI-Calculator-python/assets/37250413/55f08863-d31d-4950-bbf6-60daf70072ea)
+![image](https://github.com/reshmaharidhas/BMI-Calculator-python/assets/37250413/0b501425-3dd6-46ec-86f3-6c2cf128bebb)
+
+## Installation :electric_plug:
+1. Fork this project by clicking the icon at top-right to save copy of this project.
+2. Download the repository files from the Download section or clone this project.
+3. Import it to any Python IDE and run the application.