Can not add background image, error message does not make sense

I want to add a background image to Teams, and get the error message "Couldn't add background: Invalid image size". The image is a JPEG and has size 2048x1512 and hence inside the limits given by Teams (2048x2048). The file size is less than 2MB. I'm running MacOS 12.7.3 with Teams Version 25007.204.3374.1976, which is the most recent Teams version running on this platform.