When I took greater care about my SEO my post went “viral”. And that was small changes like changing post with listing “20 best x things” from number list to each point with H2. This went from almost 0 viewers to 50 daily. Really small things matters.
Now I have to sit and add Alt Text to my images as you suggest. It hurts that I didn’t do this from beggining as now I have to do this for over 500 images, but few per day and I’m done after some time.
Take care of small things guys, it really helps your content!