图像不会在较小的浏览器中调整大小

I am trying to place a image on the bottom right corner of my page and have it always be there. I have managed to do this but I have a problem when making the browser window smaller (which also is a problem while looking at it in different advices with smaller screens). When I make the browser smaller the image stays in the same size, and eventually overlaps over the other items (like my menu for example). Is there anyway to make that the image automatically becomes smaller together with the browser? I am trying to place a image on the bottom righ