It would be nice if the background weren't so blurred - that way, we'd be able to see the setting of the flowers. Although I can sort of make out bushes and more pink flowers.
Because in contrast with the actual flowers, the background is too blurry, and the edges of the flowers are too sharp. The two don't fit into each other, like they would in a natural photo. The sharp edges of the flowers make them appear as if they have just been plopped on top of the background, do you see what I mean? Especially since there's no evidence of depth perception - I can see an attempt, with the darker shades of petals underneath a couple of the flowers, but none at all on the background - again, this would've been less obvious if there was a bit more focus in the background.
Are the flowers vector images? Even so, I think a bit of variation in the pink petals would've helped create a realistic effect - maybe with the use of a light source?