Select your image in Aperture and use "File > Export > Version".
In the Export panel press the "+" button in the lower left corner to define your own export preset with the settings "Jpeg" and "Size to 1024x1024".
Experiment with the "Image Quality" slider, until you have a file size that is small enough. Quality "8" should give a relatively small file.
Thank You Léonie, for your quick reply.In your explanation clicking on> "File > Export > Version".
My window displays a different drop down menu.Which show a 3 panel display.The left panel > desktop user document's etc.I have to click on the Aperture logo.Go to presets > export image.Than I get the right window where I can adjust my files to the required pixels and sizes required necessary for his LUF Leica web site. Anyway I got it working albeit a bit slow as it is new to me.The DPR web site is much simpler to post , etc. The OSX version I use is 10.9.1
Could that have been the difference? Thank you so much for your help. John Basso.