How can I fit an element (pls see photo attached) above the buttom bar?

Hello everyone. I am completely new to Figma. My question is;

I mean, I created the square with lines which indicates an image. But I want to show the scroll effect and it should also work in prototype. Because I could create the look by cutting square to fit it but of course it doesn’t work when I try with prototype. Could someone please help me? Thank you very much.