I have had this issue with Accordions stretching the Images you place next to them and have noticed a lot of other people having this same problem with no real solution (at least those who don't want to use CSS or the Classic Editor).
Change the image to Fix rather than Fill. Edit the image and Crop it to your desired dimensions.
This has been the one easy solution I have found to this issue. I don't understand why they won't change this or add an option to hold the image in place, but this at least works for now.
Anyway, I hope this helps!