It might look like she lost weight, but there are signs that she hasn't.  Her legs, arms, and upper body haven't changed in size between the pictures at all.  Even if most of what she lost was in her belly first (which depends on her lipid patterns), there should have been at least a little bit lost from other areas, if not a similar amount. It looks a lot more like she took a shot with her belly hanging out, then sucked it in as far as it would go for the "after" shot.