Image ID not found in URL- so where is?

‘ve read a bunch of threads telling me that I can find an image ID in the URL of the image, but neither by hovering, nor finding it in the Media Library, does the URL of my included image have an ID#. Image in question: https://bettabelieveit.net/wp-content/uploads/2011/08/buynow.png
I need the ID to exclude it from the main gallery.

When will they just make a simple check-box option in the image gallery for which pics you don’t want included >,<
Secondly, where can I find this elusive image ID number?