On one hand, this picture by itself doesn't seem overtly inappropriate. Yes, the character's rear looks strangely prominent, but that may be just because her upper body is so small compared to the rest of her. Plus that is basically the least revealing type of swimsuit one can wear.

On the other hand, this is the same artist who made those lewd "Hat Adult" drawings, so it is kind of hard to judge the intent behind this one.
I dunno, just trying to look at this from an objective angle.