To do so you must press Browse Images button in the Image editor dialog.
After pressing 'Browse Server' button a picture browser will appear where you can choose image you want to re-use. Just double click on it.
One of most important features of this Picture browser is the integration with Flickr and Getty Images. You do not need to have own picture you can use one that some other prepared or buy commercial version of it. To choose a service you need to press a tab with their name.
In our example we have choose Flickr service. In the search dialog we have put 'lion africa' and pressed 'Search' button. After while a collection of pictures related to lion has appeared.
You can browse your search result with Previous and Next button.
If you have found a picture you want to publish on your page just double click on it. Please note that Getty service while is offering much better quality of pictures that Flickr is not yet fully supported and you cannot buy and publish pictures yet. This feature will be available in near future.