When you attach an image just clik done, when you clik insert inline it attaches and inserts the image.
Your first image in this thread is the inserted (embedded) image.
Embedding is useful if one wishes to put an image in between text or other similar applications, in which case you will have the double image, some board software allows using one or the other, some allow embedding full sized image and then attaching it as a smaller image at the bottom of the post.
Different versions of VB use different rules.