As you can see (except for the IE users), I could achieve equivalent results for the first 2 sets by using "display: table;" and "display: table-cell;" in set 1. However, "display: table;" and "display: table-cell;" are not recognized by the IE (even version 8), according to w3shcool.
Before I discovered "display: table;" and "display: table-cell;" I tried many combination of margin, height and float (as you will see in http://www.maitrebart.net/exphotos/lapoc/fleuve.css) without any success. My guess is that I was (again) placing all those css qualifiers at the wrong places.
Can anyone knowledgeable indicate me how to make set 1 appear as set 2 without using the "display: table;" / "display: table-cell;" combo, so that IE users will enjoy the same experience as the others? ;) Ho! And by the way, I wish not having to specify any fixed width or height neither (px or %). Because I don’t want to retrieve an image’s size and then go back in the css file every time I add a new set in the page.