How to fix an image stick on the top of the footer

Hello everyone and thanks for the help in advance!
I want to have a color bar image just stick on the top of the footer on every page, even when all browsers magnify, it doesn’t appear to have a space within.
How to make it? :smiling_face_with_three_hearts:!
2020-03-21_145552 拷貝|690x152