Why has this changed?
Picture Australia was fully migrated into Trove on 28 June, 2012 and the separate service turned off. As a result we've replaced the old Picture Australia search box with a Trove search box.
Do I need to do anything else?
Not immediately, no. But eventually you will want to replace the code for your Picture Australia search box to a Trove one. Instructions on how to do this are on the National Library's website.