The postcards have un quotes from Bob's Burgers;I think they are working well as a theme. The design accomplishes to execute the concept very well.
It is clear what I am viewing and I do understand what she is trying to convey. For clarity, I don't think there is anything that needs to be worked on.
The design is straight-forward and clean; however, I think she can add some contrast in her cards. Currently, they all have characters on a white background. I would suggest making the white backgrounds colored so that she will have some contrast — also I think it will look more fun.
These cards are aesthetically pleasing. The aesthetic is consistent and workes well with the concept.
I think when the images on a desktop size they are slightly pixelated and fuzzy. If possible, find images with higher resolution. Also, for the second card, the text is too close to the images so give more space there.