Your images do not contain transparency. Centering looks for non-transparent edges.
OrbiShare: Why did my uploaded Orbigraph disappear?
Trial OrbiShare accounts have a single entry that is cleared every 14 days. When your Activation Key is added, your OrbiShare account will have 4 entries that are never cleared.
OrbiShare: Where is my Activation Key?
When you purchase Oribgraph Creator, the key is emailed to you. You can also see the key by running Orbigraph Creator and selecting 'About Orbigraph Creator' in the Options menu.