Your image links are identical, and so are your images. By the way, please see How to add images to a Biostars post to add your images properly. You need the direct link to the image or the HTML embed code, not the link to the webpage that has the image embedded (which is what you have used here)

You don't need to switch to imgbb, but you do need to get the direct link to the image and use the Image button on the toolbar.