[scribus] Placing /Scaling and file image/PDF size

[Roger]

<snip>> Now that I know that what I am wondering is this: when the image is
 >> >> scaled to fit the frame, does it reduce the image file size to reflect
 >> >> the newly scaled size?
</snip>

I usually create image boxes to the approx dimensions I need on a Scribus page 
then scale the intended image to slightly larger than those dimensions.
First I crop it  and enhanse/recolour the image if necessary then scale it.
Roger