Caesium can reduce the size of pictures up to 90%, preserving the original visual quality.Caesium allows you to save a lot of space on your hard drive and quickly upload your pictures on the web (on sites like Facebook, Google+ etc) saving a lot of time. Also webmasters and bloggers for instance need to make sure the images they post on their websites are optimized, to avoid prolonged loading times for their visitors. The software allows you to view instantly the compression results, helping you to decide how much optimization you need. Caesium can set different compression levels to each image, saving a lot of time, ensuring great results! We were confused in testing software where Caesium kept warning the was know output folder even if you specifically state the output folder to Caesium under Tool> General. If you also select the check box for "use the default output directory when none is specified. That will override having to tell each file where to output too.