All women will agree that the choice of the bag is not one to be taken lightly [:)]. However, on a long torsoed-shorter legged body, which kind of bag one wears is not simply a question of style or practicality, but of strategic importance, as where exactly the bag falls can completely make or break a silhouette.
The trick for shorter legged women is to choose bags that fall in the right place: usually exactly on the top of the thighs/hips, to conceal and elongate. Too short or too long bags can both highlight the crucial leg-break area, and can ruin even very well chosen outfits, whilst bags that fall in the correct place can fix less flattering ones by simply hiding the 'problem zone'.
See a negative and a positive example, courtesy of the lovely Rachel Bilson:
The correct position can be achieved with either bags worn in the crook of the elbow [beginners] or shoulder bags [advanced]. Envelope bags also work, but how often do we wear those in real life...?
Medium sized or larger bags tend to work better than small ones for the simple reason that they hide more. For the same reason, less structured or unstructured bags [hobos on the shoulder, slouchy ones on the arm] tend to be the best. Very structured bags can look stuffy and also really highlight curves [not in a good way].
Crossbody bags are a tricky thing. They can work, but require particularly careful choosing. The strap should ideally be adjustable so you can determine where exactly the bag falls. Their size can vary [with these, it is easier to get away with small ones - although beware that small bags on long straps can highlight long torsos], but the shape is best if not completely flat. Experiment also with where you want to wear it: on the side, at the front, at the back?
Of course, we do find ourselves in those situations when our best bags just do not look right - when either the texture or the colour or the style does not work with our outfit. For these times, have a shorter strapped bag ready, to be carried in your hand - this way it will not interfere with your silhouette. Just make sure you do not inadvertently fling it over your shoulder.
A few examples -- compare the left column to the right and see how even subtle differences can change things: