I think there is a common misperception that corsets were invariably intended to create a slim figure with a small waist. For older women of the period in particular, this was not especially true. Although they could use them this way, the main reason respectable women wore corsets was to achieve a restrained shape, so the bust and hips were not free and perceived as immodest. Moreover, the shape of corsets followed the fashion. From 1909, corsets developed longer lines, no longer striving to achieve by then outmoded 's' bend shape. Here are an illustration from a corset advertisements from 1912-13, and two from 1914, when corsets became even less restrictive (comparatively speaking):
Allowing for the exaggeration of the illustrations, one can see that the corset of that time did not pull the figure in at the waist and, if made for an individual woman (as Alexandra's corsets certainly would have been), would have fitted her body's measurements. There was also provision for letting corsets out at the lacings at the back, as was mentioned in earlier posts. It is in fact possible to discern under the filmy top of Alexandra's dress in the photo, some diagonal lines which could indicate boning from a corset, but even if these were not, the illustrations demonstrate that a fuller figure did not mean corsets would not be found supporting it. Indeed, the wonderful 'nuform' corset illustration shows the active life a woman was supposed to lead wearing it.
