Why do Firefox and Opera ignore max-width inside of display: table-cell?

Question

The following code displays correctly in Chrome or IE (the image is 200px wide). In Firefox and Opera the max-width style is ignored completely. Why does this

Answer 1

Setting width: 100% does fix the problem, but it introduces another one. In WordPress you don't want to set width: 100% to an image. What if the image is medium-size with a width of 300px, what then? I've been using classes to set the width to 50% on medium-size, but what if the image is smaller? Then it will get stretched. In webkit browsers it works with width: auto; max-width: 100%; but since Firefox, Opera and IE ignore that... that's a huge problem.