This demo replaces existing dimensions within image URIs with the updated request dimensions. There are only 3 different CSS classes, but 6 images. This shows that one CSS class can be applied to multiple images even though the src URI changes per image.
Photo by Master Sgt. Andy Dunaway
Photo by Benh LIEU SONG
Photo by Alexandre Buisse
Photo by Sam Garza
Photo by NASA, Astronaut Michael Edward Fossum
Photo by Alvesgaspar