a) This is not the correct newsgroup for your question (unless you're
looking to do this programmatically, which I don't think is likely).

b) When an object is selected, size handles appear on each of the corners
and at the mid-points of each of the sides.  These look like small white
circles with black borders.  Drag these to resize your object.  You can make
it larger or smaller.  Use the Ctrl key whilst dragging to resize about the
centre, rather than the opposite corner.  Use the Shift key whilst draggin
the corner handles to maintain the aspect ratio (ratio between the width and
the height - i.e. you don't stretch the picture and distort it).