Selfie cameras typically have really wide angle lenses, so you can easily frame yourself with your background when held at arm’s length.
However, wide angle lenses at close range will heavily distort your face, making your nose appear bigger, and your face smaller. THIS is why you look different in selfie cameras.
The way you are viewing the image changes everything. Or rather, the way the machine that takes the image you view takes the image changes everything. To wit:
https://2.img-dpreview.com/files/p/TS560x560~forums/59651532/97d6cb27f73a449d93865a8f3837c12c
https://s23527.pcdn.co/wp-content/uploads/2017/01/20.png
https://cdn.dpmag.com/2017/11/004-Focal_Length_Comparison-1024×545.jpg
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