Third batch of refreshed images (#2545)

Author: lidiazuin

modules/ROOT/images/federation.svg

@@ -66,7 +66,7 @@ Based on this, and their own assessment of the patient, the doctor may make a di
 * `date`: date of diagnosis
 * `description`: additional doctors' notes
 
-image::security-example.png[title="Healthcare use case", role="middle"]
+image::security-example.svg[title="Healthcare use case", role="middle"]
 
 This same database would be used by a number of different users, each with different access needs: