Good news - the On Sale extension has become more flexible! Add label images much faster - with an ability to use an existing image you can avoid constant images uploading and add them by mere entering their path!
One more advantage you gain updating On Sale to version 2.1 is discount labels threshold - now you can set the minimum discount threshold for labels to be displayed. Manage labels displaying more efficiently!
And the last novelty of the new version is that IE moves description below the image no more.
Find the On Sale features, screenshots and complete changelog on the extension page.