Why does unwanted opacity appear on my site's images?

As soon as I add an image, an unwanted level of opacity automatically shows up on my transparent images on my site.

I have explored changing opacity and transparent backgrounds with no success.

You can see it on my site: souvenirshop.goodweekend.co

Any help would be greatly appreciated!

@mushparker

yes, please try this code

  1. Go to Online Store->Theme->Edit code
  2. Asset->/theme.css ->paste below code at the bottom of the file.
[data-image-loading-animation] {
  background-color: transparent !important;
  -moz-animation: none;
  -o-animation: none;
  -webkit-animation: none;
  animation: none; }