How can I make thumbnails the same size in my portfolio? Help please

This is the link.
I want them to be the same size but I am stuck on this, something is always missing. Now for example they are different size and the sixth one disappeared.
Thanks for any help. Much appreciated.

Your sixth image tag has a bit of a type:

<img class="" alt="gray6">

As for the size of the others, it’s a bit tricky because they all have different aspect ratios. I would set the width explicitly, set the height to auto, and make sure that overflow is set to hidden. Example:

.my-img {
  width: 100%;
  height: auto;
  overflow: hidden;

Try using this class on your images.