I agree with @BruceP she does not look fat or underweight, she could probably stand to gain 1 pound, but now if I were you I would just watch to make sure she does not lose anymore. For now, she looks just fine. Now that you are aware of it you can pay attention to it. The first and second pics she looks good, the third through fifth make me think she could gain a pound.
Now you are with her all the time and pictures can be deceiving, so if she looks more like #1 and #2 the most I think she is good.