I have a fresh Confluence 6.3 install (official Docker image) and when I edit a page and want to insert new emoticons, I can't see any pictograms/images. Tried it with three browsers - the images are always missing.
Screenshots:




Thanks!
UPDATE:
The isssue is solved now. User error 
Since I am using Docker, I have created a docker-compose.yaml file. The relevant part looks like this:
version: '2'
services:
confluence:
image: atlassian/confluence-server:6.3
restart: always
ports:
- "127.0.0.1:8090:8090"
depends_on:
- postgres
volumes:
- confluence-data:/var/atlassian/application-data/confluence
- /opt/docker/mount/confluence-cfg-mount/server.xml:/opt/atlassian/confluence/conf/server.xml
- /opt/docker/mount/confluence-cfg-mount/server.xml:/opt/atlassian/confluence/conf/web.xml
As you can see the last line mounts the *contents* of server.xml into the web.xml file. Confluence rightly complains about a directive missing - well the entire web.xml was missing but ok:
23-Aug-2017 16:14:52.643 SEVERE [localhost-startStop-1]org.springframework.web.servlet.DispatcherServlet.initServletBean Context initialization failed
confluence_1 | org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'defaultServletHandlerMapping' defined in class org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.HandlerMapping]: Factory method 'defaultServletHandlerMapping' threw exception; nested exception is java.lang.IllegalStateException: Unable to locate the default servlet for serving static content. Please set the 'defaultServletName' property explicitly.
The weird thing though is that I did edit the web.xml file before because I changed the session timeout. I don't understand how Confluence was able to change my session timeout even though the web.xml file had the wrong contents...
However, if anybody else stumbles over this - you're welcome. Thank you all for your help. Special thanks to Ann for her dedication and perseverence 