8 months old - average size?
 

My puppy, Trig just turned 8 months last Saturday. I'm concerned about his weight/height compared to other GSDs I see at the dog park.

I haven't weighed him recently but I've attached a picture for reference.

I feed him twice a day, once in morning and once at night. 2-3 scoops of Blue Buffalo Puppy.

He doesn't seem hungry often but he'll eat the whole portion but no more than what I give him, he eats his treats no problem.

Should I try another food? Is his size average for his age?

From the picture, he looks tall.

What does he weigh?

He is only 8 months, and the dogs you're comparing to, might very well be full grown.

Don't worry about what other dogs look like - concern yourself with the health and wellness of YOUR dog. Dog needs to be lean - especially when growing. You should see the last two ribs, firm/taut skin, nice tucked up underline - feed accordingly to maintain his weight.