Image in header only shows on home page

In my header.php file i’m using an “img src” tag to display an image. I have an “images” folder at the root of my htdocs folder. When I’m on my home page I can see the image, but when I’m on any other page the image can’t be found. This makes no sense to me, because the header, home, and all other pages are located in the same place, so why would the path to the image only work for the home page?