[Klug]

Broken image is a known issue, it seems to be fixed in 5.0.2 :
Bug 21959 - Inline image attachment not showing correctly

Zimlets problems too (fixed in 5.0.2) :
Bug 9858 - Zimlets do not load in any new window (compose, detached view, etc)
Bug 23688 - com_zimbra_date zimlet not working.
Bug 22653 - Zimlet loading fails with NPE if any zimlet in COS is missing from the host

Have a look at your PM.