I uploaded AI generative images 78 images were rejected due to quality issues

It's quite surprising that you only waited a week for your assets to be reviewed. Most AI Contributors are waiting 2 months or more. Are you a first time Contributor? Have you had prior sales if AI assets ?

220.jpg - the image looks soft and low res with some jagged edges, but the main reason for rejection was probably the border in the left edge 

218.jpg - same here. There's a border in the right side, stray objects at the top, and the bird in the right is resting on a leaf rather than a branch. These types of details matter and indicate that you're not inspecting your images carefully.