Sitecore introduced new speak dialogs in the interface with version 7.1. These new dialogs use search for browsing the assets in the Media Library. Since this release, there is a known bug, which sets the full image url as ‘Media folder’ and not the folder in which the image is stored. This results in a ‘No items found’ message.

Media dialog no items found

I can still reproduce this issue, even in version 8.1. There seems to exist a hotfix, but a quick workaround might be enough for you. The workaround is to use the “Three view” mode by default, as this mode works correctly. Users can switch to this view from the dialog, but it would be easier to make this the default mode.

The treeview dialog correctly shows the existing image

To change the default behavior, add a custom config file like /App_Config/Include/Sitecore.Speak.Applications.Custom.config and patch the default Speak config to use the treeview dialog.

<?xml version="1.0"?>
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/" xmlns:set="http://www.sitecore.net/xmlconfig/set/">
  <sitecore>
  <overrideXmlControls>
          <override xmlControl="Sitecore.Shell.Applications.Media.MediaBrowser" with="/sitecore/client/applications/Dialogs/SelectMediaDialog">
                <patch:attribute name="with">/sitecore/client/applications/Dialogs/SelectMediaViaTreeDialog</patch:attribute>
          </override>
  </overrideXmlControls>
  </sitecore>
</configuration>

Until Sitecore fixes this bug, you will now have a simple workaround when editing previously selected media items.