Based on this simple idea:

img:not([alt]) {<br> transform: rotate(0.5turn);<br>}#css#a11ypic.twitter.com/lvXPNzN7s8

— Filip Dalväg 🇸🇪🇪🇺🌍 (@FrontEndFilip)August 28, 2019

with a variation from @pauldwaite

Blur inaccessible images

Drag this link to your bookmarks (or favorites) bar and click to use.

Applies the following CSS to your page:

img:not([alt]) {filter: blur(20px); }