Images are always cut off on flip cards. What I'm using is not big - but it goes half way up the flip card and looks odd.
We apologize for the inconvenience caused by the image insertion problem.
Could you please let us know which tool you are using to insert images and what is the file format of the images (jpeg, png)? Are you using Creator+?
I am also including a few articles about inserting and updating images with Brightspace Editor:
We appreciate your cooperation and patience.