Try to make images look good

TUTORIAL.md

 
 Once you’re configured your phone, computer, and Apple ID to work, you should be able to open the app and see screens like the ones I captured on my iPhone 6s Plus.
 
-|<img src="./static/iphone-login.png" width="200">|<img src="./static/iphone-register.png" width="200">|<img src="./static/iphone-forgot-password.png" width="200">|
+<div style="text-align: center">
+<img src="./static/iphone-login.png" width="250">
+<img src="./static/iphone-register.png" width="250" style="margin-left: 20px">
+<img src="./static/iphone-forgot-password.png" width="250" style="margin-left: 20px">
+</div>
 
 ### Android