Hello @LondonCollegeofClinicalHypM ,
You can add multiple images to a single email, even if they're all larger image file types. If a recipient's email client or internet connection is unable to properly view these images due to their size, that isn't something we're really able to control. The 5 MB upload limit is already taking such instances into consideration for the sake of deliverability, but beyond that it's something the recipient needs to handle.
If you're particularly worried about your recipients being unable to view your email properly with several large images, I'd advise adding a view as webpage link at the top of your email.
For more info regarding image imports:
optimizing images for import
editing / resizing images using the built-in image editor
common library upload errors and troubleshooting
... View more