Add credit over image

Hi,

I would like to add credits on the corner of pictures on a page. I know how to do it for the banners, but I don't know how to change it for pictures in the content.
I would want to add credits to the tree pictures in that page: https://www.melissamarschke.ca/research

For the banners I have that CSS code
/*Text Based Photo Credit banner front page*/
section[data-section-id="64794e36eda473789492e4f2"] .section-background::before {
  content: "Image credit: Furqan Asif";
  position: absolute;
  font-family: 'Poppins';
  font-size: 15px;
  font-weight: 300;
  color: #fff;
  bottom: 1vw;
  right: 1vw;
  z-index: 99999;
  display: block;
}