Saving JPGs in XnView

I've been asked how I manage to save good graphics in small files. This JPG of the lovely Georgia Horsley, Miss England 2007/8, is only 8Kb. (Note the cross of St George on her crown.) The answer is XnView, a French graphics utility by Pierre Gougelet. I'm using the 1.68 version (2004). It's only 10Mb; it's free; and it does more than some packages that occupy 100Mb and cost £50. When you click the Save As button in XnView, the usual Windows box appears. In the bottom right corner you'll see Options. Click that and a sliding scale from Lowest to Best appears (the picture quality). Saved at 100%, this photo took up 54Kb. Too big. What I usually do is save at 25% (the minimum for quality), 30%, 40% and 50%, then see how big the JPG files are and how good the graphics look. The 40% save gave me reasonable quality in only 8Kb. Why is this important? The bigger the file, the longer the load.