I am using Windows 10 Enterprise Version 1709 Build 16299.309. I use the Windows 10 Mail App in German. When inserting an image to a newly created e-mail, options are available in the picture/image tab (Bild in German).
For the options to crop the picture, inches are used as units, both in the options for Bildposition and Zuschneideposition. I don't know, if this is a translation error or a bug in the application. In Germany, we are using centimeters as units. For comparison, the units in the second screenshot below regarding the image size are correct. Additionally, the texts X-Offset and Y-Offset are untranslated.