I just noticed than if you ‘forward’ an email containing photos Apple mail will reduce the quality and size of the photos. I noticed this when I forwarded some photos to myself from one computer to another and they shrank to about 1/10 of the size! Thankfully there is a way to change this to make sure your images forward at full size.
When you forward an email containing a picture, Apple Mail App may reduce the picture size. This does not make sense to me at all. When I press ‘forward’ I want the original email forwarded exactly as it is without any changes. There should at the very least be a dialog box saying ‘This email will be large to forward, would you like to reduce the image size: Yes/No?’ There is no such option, but you can change it manually.
Have a look at the bottom right of this screen shot…
It says ‘Image Size: Medium”
Be default Apple mail is reducing the size of the forwarded images. You probably don’t want this to happen, so select ‘Medium’ and change it to ‘Actual Size’ like this:
Now the images will be forwarded full size.