Generally speaking, Word inserts a picture at 100% size or as close as it
can get within the margin constraints. If 100% size is 7" wide, for example,
and you have the default 1.25" left and right margins, then the inserted
picture can be only 6" wide (86%).
If you want your picture to extend beyond the margins (to cover the whole
page, for example), you must change the wrapping. The default wrapping for
Word 2000 and above is In Line With Text (which is why the picture is
constrained by the margins). Change this to Square or Behind Text or some
other wrapping style, and you will be able to move the picture freely and
restore its size to 100%.
