Is there a way to center a photo after clicking on a link… as in <a href=“images/blahblah.jpg”> etc…
They open but are always in the upper left portion of the window.
No, if you just mean a direct link to a standalone JPEG file then it is up to the browser to just render the image file. Of course if it were a link to another webpage containing an image you could position the embedded image on that new page, etc. Alternatively something like a “Lightbox effect” using JavaScript may centre position the image on the current page (overlay images on top of the current page) if that is what you had in mind.
Firefox seems to do that now by default. But as Robert says, the easiest way to ensure this is to make the link a link to an actual page, o which the images is centered with your own code. You can then style the page any way you like—with fancy borders etc.