The new Wix blog is still struggling with being optimized for Pinterest. At least two issues remain:
1. Photos that are in galleries/collages don't have the Pinterest hover button.
2. Wix blog isn't compatible with the "save from site" Pinterest functionality. I attached a screenshot below of what happens when I try to create a pin from my blog URL.
Pinterest prefers for you to pin different photos from one URL rather than just the same display image over and over. Because of this, it's important to prioritize making all images from a blog discoverable by Pinterest whether or not it is in a gallery or pulled from the URL.