Solution is probably posted. But just to avoid possible confusion I'll mention that get_template_directory_uri() is the path to your current active theme. So your images folder shown in your code must not be in your parent directory.
Chances are you know this comlucom but I don't like to assume anything when it comes to troubleshooting.
If you still have problems. Try visiting the image directly and confirm the full path. Then paste that into your theme. If your theme is not going to be used anywhere else, it is fine.
If get_template_directory_uri() works for you. You may still want to replace it with the full path created by get_template_directory_uri(). Less use of functions makes for a faster theme.