Should the crease of my breasts look like this when sitting down? (photo)

This appearance means that there is some excess skin tat has pulled downwards with the weight of the implants, and especially in a seated position which creates a crease. I wouldn't say that this is a normal, but it is a complex problem; one that may be alleviated with supporting the implants in the lower quadrant with another procedure. There are options available, but a full assessment would be required.

Thank you for your question.  It's hard to answer this with out an in person evaluation.  I would suggest seeing your surgeon and addressing your concern about the excess skin.  Best of luck to you. 

Thank you for sharing your question.  This is difficult to say without an in-person examination but it may be due to some skin stretching between the breasts, or a bit of excess skin.  Talk to your physician as they can look at your before, and current, pictures to see the reason for its development.