I have used the drop-down menu that appears when "exporting" and selected the jpg-original size option
When you export a version with "jpg-original size", Aperture will render a new file, with the pixelsize (width and height) of your original image file, but tat does not necessarily mean that the file size will be equal to the file size of the original image file. The filesize will depend on the jpeg quality setting. The lower the quality value, the smaller the file size.
I'd suggest you check your "jpg-original size" setting. When you are sharing or exporting, select
"jpg-original size" and then set the Export preset to "Edit". Check, if the "size to" is really set to "Original size" and check the jpeg-quality.
With that settings (jpeg quality 10) my Aperture version will export a version of an 4.63 MB Jpeg original file as a new file of 2.7 MB.
Edited versions will always be rendered new; if you want to get as close to the original quality increase the jpeg quality setting in that panel.
Or share the original and not the edited version; that will export the original file as it is.
Now I've got it - I slid the quality slider up to max and got the expected file size when I exported to desktop...also size stayed OK when I dragged int Mail...still same issue of file reduction when I use "Share" to email directly via right click mouse button, but there must be a control in email share preferences...a more consolidated drop down for all of these possibilities would be nice...but you've solved my problem.