What is the difference between getImageScale(f) and getProperty(f,imageXScale)

[manufv]

hi,
scribus 1.5.7
On a frame I 'll read imageXScale, imageYScale
the doc instruct to use
imageXScale1,imageYScale1 = scribus.getImageScale(imageFrame)

but there is too
imageXScale2 = scribus.getProperty(imageFrame,'imageXScale')
imageYScale2 = scribus.getProperty(imageFrame,'imageYScale')

on same frame, I get theses different values

imageFrame.imageXScale1   <1.0 (0)>
imageFrame.imageYScale1 <1.0 (0)>

imageFrame.imageXScale2   <0.75 (0)>
imageFrame.imageYScale2   <0.75 (0)>


Is there some one who knows the difference ?
I must say there is a Rotation of 4deg, is it relevant ?

Thx
Manu