I am a hair shorter than you and I started heavier - but, my first 50 pounds didn't show all that much. Actually I am a little surprised by your 6 pants sizes - my first 50 were only good for 1 pants size plus a little extra - there is not a ton of granularity in those fat-lady sizes I have to wear.
It's unfortunate but true that the bigger you are, the less it shows when you lose a fixed amount of pounds shows. Weight goes with volume, and volume goes with diameter cubed. A big change in volume -> a small change in diameter.
So - go for some cues other than how you look in pictures (who looks good in pictures anyhow?). Since you have lost 6 pants sizes, why not step into those old pants 6 sizes ago, and then you'll get a very tangible measure of how much you've changed. Or go hoist a couple of 25-pound sacks of cat litter and think about hauling all of that weight around all day.
I'm very sorry that the pictures are disappointing you but believe me, it's not all for nothing - try some of those other ideas and find some other way to experience the loss other than how you look in pictures.
PS: I don't think you look exactly the same - but I don't think I'm going to convince you of that.
Most people can't see anything positive in pictures of themselves.