Windows 10: Windows 10 mail

Hello, I am new to Windows and have a question about windows 10 mail. When I attempt to generate a new email and I want to attach an image, I click on INSERT and I notice I have a couple options, one is to insert a file or I can insert a photo. I first started with inserting a file and when it was added to the body of the email it was just a small section displayed of the entire image, similar to a thumbnail. Once I sent it to myself as a test it displayed fine on the other end so its not a big issue. Then I noticed I could sent attachment as a photo also, when I attached the same file to the email the attachment showed the full image and not just a section of the image, which is what I would prefer. I then thought that that would be my best option but I sent another email test to myself with the same image attached utilizing the two methods and although I received then fine, the file attachment was at a much higher resolution that the photo attachment. I am not sure why this is. It was the same file. If that is how it will treat the attachments then I really only can use the file attachment method due to it's higher resolution, but I don't like the preview of the file attachments in the body of my email because it is a clipped image. Any thoughts I would greatly appreciate. I would love to be able to attach the best resolution and still be able to see the entire image I an attempting to sent. I hope this makes sense.

Thank you

:)