Reduce jpg file sizes

I take a lot of photos in jpg format. I want save disk space by lowering the jpg quality from 100% down to 90%.

The Convert Image function (right click menu) will only let me do this if I am converting files from another format into jpg.

I do not want to reduce image sizes, just the jpg quality.

Is there any way to do this? If it is only possible with a button command or script could you please suggest one please?


There are also free utilities like fileminimizer to do these things

Thanks Leo, that worked like a charm!

Thanks for your suggestion hpearce. I will have a look at that program, but Leo's idea may be all I need.