I have the same problem as the topic starter. I'm using Outlook 2016 in combination with Paint.net 4.2.1.
The steps I took:
- I captured a window using ALT - PrtScn
- I pasted it into an outlook email message and sent it to myself
- Once received, I copied the image and paste it into Paint.net
- In Paint.net it is displayed with the full height, but the width is cropped to 795 (pasting images smaller than a width of 795 are copied without problems)
- Using clipboardic I can see that the image was copied as "Rich Text"
When i copy the image from Outlook to (windows) Paint, Copy it from (windows) paint and than paste it in Paint.net, everything is ok. I see the complete width of the image. The type according to Clipboardic is then 'Image'.