Okay, if it's a morph it's a very well done one. But how about the stretch lines going horizontally on top of her blouse? How do you explain that? That seems normal to me only if the the fabric is being stretched some.
It is an obvious morph and there are 4 basic mistakes that give it away:
1. Simple scale up error - when you enlarge anything it is effected by gravity, the mass is greater. Breasts are mostly skin flaps full of fat and they react differently as their size increases. The breasts in the image are not placed, shaped or reacting in a manner consistent with that size. One can not simply enlarge the breast X2 (a cubic volume change) and expect it to retain the "look" of the smaller set.
2. Not everything scales up as breasts increase - the most obvious are those very stretch lines. These are lines of shear expressed as deflection of the fabric. The fabric, regardless of the area it covers has a set limit to how often it will express these lines. The number of lines & length will increase as the region loaded increases, but the width (perpendicular to the load) of those lines will not. You would get more lines, not wider lines.
3. Secondary lighting effects - light does not like to turn corners so the more it has to the darker the shadow becomes, reflected light complicates this, but again the larger the object the deeper the shadow as more reflected and incidental light is infringed. Thus the degree and extent of shadow would be much greater than we are seeing. In lay terms the shadows and highlights are off. Those are the shadows of a much smaller and less projecting set.
4. These breasts exceed basic anatomical ranges that would be exceptionally rare to see with natural breasts. One basic test is the degree of breast flair. As size increases they move from almost hemispherical thru cone thru teardrop to pendulous. Natural breasts do not continue to retain hemispherical proportions. In very large natural breasts most of the mass is in the lower 1/3 simply to accomplish that size as you start to move well down the chest wall. Interestingly the nipple will stay mostly on a vertical axis and only move downward - neither of these is true in the photo. Not only have the nipples move horizontally but the outer edge of the breast is now well outside the mounting points of the rib cage.
If one looks at the really good morphs, the ones where you have to stop and really look, the breasts look believable because they look heavy and interact with the surroundings. They are more contorted due to gravity and sit lower on the chest wall. Also there a no pixel artifacts or blur edges at the splices.
In a side note: There is a thread at the BEA that even deals with the ability to see breasts from behind - a very rare anatomical trait for natural breasts that feels counter intuitive at first. Yes, fake boobs will do this and a gal can push them outward for this effect but they normally will not exceed the chest wall width naturally without intervention. This has to do with how the breast pocket forms on the chest wall.The morph image is still not an implanted gal as she still would fail points 1, 2 and 3.