He looks alright in that picture, however feeding just parsley (or at least I think that is parsley in the picture) isn't a healthy diet of greens. Also, it should be chopped up and the large stems removed. A mix of at least two kinds of stable greens should be in the green mix, such as collard greens, dandelion greens, mustard greens, turnup greens, endive, escaroli. Other greens that can be added are parsley, kale (in small amounts), chinese cabbage, summer squash, zuccini, bell peppers, etc.
In the picture, it's hard to tell if he has fat deposites on his head or tail. Behind the eyes, should be two small humps, which would be fat deposites. The tail base should be nice and thick. As she seems to be eating whatever you offer, and if he doesn't seem to be growing and showing some fat disposites (too fat isn't good either), I suggest taking a stool sample to your vet for a fecal, to see if he has any parasite problem. A large concentration of parasites in his system can explain slow growth or lack of weight gain in an otherwise healthy eating dragon.
www.beautifuldragons.com has a great nutrition list of greens and vegetables and how frequent each type can be fed to your dragon. if you haven't checked it out already, I deffinitely recommend taking a look.
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PHLdyPayne