Image Quality is terrible (just recently) with wordpress

I actually have no idea what version of wordpress that I am using for my website. the website is: https://www.heathertufts.com

Hope someone can help:

I am a photographer and my website is my official portfolio- problem is (and it has never been a problem before), the image quality is suddenly degraded. When I load up my photos, they are slightly foggy compared to the originals. Also when trying to showcase a featured image, the featured image is VERY contrasty and the colours are completely off. I don’t know what to do!

For instance- this featured (Black and White) image looks green and way to contrasty.
https://www.heathertufts.com/blog/wedding-bells-at-the-doctors-house/

The featured image is also in the portfolio- image 13 of 25. As you can see they are completely different!

Please help- anyone!

Thank you,

Heather