Fix broken image because center tags
I removed the center tags to show the validation flow correctly.
@@ -132,9 +132,9 @@ but the pinned certificates will take highest priority for validation, followed
by the pinned CA, followed by TOFUS (TOFU over HTTPS). The diagram below
describes this validation flow:
-<center>
-![Trust pinning flow](../images/trust-pinning-flow.png)
-</center>
+
+![Trust pinning flow](https://cdn.rawgit.com/docker/notary/27469f01fe244bdf70f34219616657b336724bc3/docs/images/trust-pinning-flow.png)
+
Only one trust pinning option will be used to validate a GUN even if multiple
sections are specified, and any validation failure will result in a failed
