I don't think it does: it moves the graphic towards the right side of the window, not of the page. The Zoom slider changes the view of the document but not any of its contents. If you increase the zoom factor, the inserted graphic will appear to increase in size, but that is only because you have magnified the entire page. The graphic is unchanged in size or position on the (printed) page - a fact that you can quickly confirm by going to File | Page Preview (or clicking the Page Preview button in the Standard toolbar). It moves to the right of the LibreOffice window because by increasing the zoom factor you have enlarged the page display so that it now spills off the right side of the window.
To change the size of an inserted graphic:
o Click the graphic to select it - so that you see the eight coloured handles.
o Drag any of the handles to change the size. To retain the original aspect ratio, hold down Shift before releasing the mouse button.
Alternatively:
o Right-click the graphic and go to Picture... | Type.
o Tick "Keep ratio" if desired.
o Adjust the available options - in particular Width and Height under Size.
This is all described under "Resizing an image" on pages 259 and 260 of Chapter 8: Working with Images of the Writer Guide (for version 4.2), available from
http://www.libreoffice.org/get-help/documentation/ .
I trust this helps.
Brian Barker