I'd disagree that this would be of no concern. Your biggest concern I'd imagine is going to be your mobile experience. Say one image is linked but another is not (I'm sure neither are but stay with me), in this case a crawler (or user) gets to the page can't click on one image versus the other.
In GSC you may see that you're getting a warning for images clickable elements being too close or something of the sort. It's just a mess and you should be worried about it in my opinion.
If the images need to be one, I'd do so in a photo editor, export the single image and add the alt to that.
One more note, though this isn't going to skyrocket your organic traffic overnight I can't stress enough building your site and processes correctly the first go around. It's a minutia until you get hit with an warning or have a poor mobile experience reflected in your rankings.