Not an answer but rather an explanation of why this occurs.
On your profile page, the original large-sized image (https://i.stack.imgur.com/Rv5jh.png?s=328&g=1) is linked. Hence, when it is displayed on your profile page (as seen in Picture 3 in your question), your profile picture appears to have shrinked in width.
However, in most other places, a thumbnail (https://i.stack.imgur.com/Rv5jh.png?s=128&g=1) of your profile image is displayed. This makes your profile picture cropped at its sides.
This could be resolved by the SE developers by adding
object-fit to the
<img> tag on the profile page, i.e.,
<img src="https://i.stack.imgur.com/Rv5jh.png?s=328&g=1" alt="" width="164" height="164" class="bar-sm avatar-user"
^^ this part is added
style="object-fit: cover;" is added, the result is as follows:
For comparison, this is how your profile picture currently displays: