I have plenty of pictures of all my children. More of my first, but still lots of all of them.
The biggest difference is that the first ones are organized neatly in labeled books. The second’s are partially in books and partly hither and yon. And the third and forth ones have all their pictures stuffed in a drawer.
I keep meaning to get to it. One of these days…
Only because we made a concerted effort to take as many. It was a bit easier for us. For our first born we got a membership at the JC Penny portrait studio. So every single month during her first year we went for pictures. Each month with a different theme. After 12 months we dropped down to once every 6 months and then now it’s once a year. So when the unexpected 2nd child came along we just did the same thing. Every single month to the studio for pictures. Of course it became a lot harder to come up with those themes that weren’t exactly the same as for the first born, but we’re glad we did it.
The biggest problem I’ve found as a parent is that it’s almost impossible to take a picture of the youngest without the older child wanting to be in the picture. So you’re never going to have the same number of pictures of your second child by themselves simple because the oldest won’t let you!
Same in my family. Tons of pictures of me, relatively few of my sister who was born slightly less than two years later. Then hundreds of pictures of my next sister who was born nine years after sister #1.
Yes, she did. All it had in it was a recipe for Apple Brown Betty.
I’m the fifth of five. Trust me, there are NO pics of me. My mom didn’t even keep all my school portrait photos! But she keeps the eldest child’s recital tu-tus in the closet.
Yes, I have issues. What gave it away? 
I’m the elder of two children. There are hundreds more pictures of my little brother than me. Especially in adolescence and adulthood-- There are maybe 20 pics of me as a teen and 40 as an adult, but there are dozens and dozens of CDs of digital pics of him as a teen. And he’s stupider than me! (Can you tell I’m jealous?)
I have an older brother and a twin sister; there are more pictures of him than my sister and I, but we still have a decent amount of photos too. What bothers me is that there are NO pictures of me by myself, but there are several of my twin by herself. She was always more charming and camera-aware than I was. She still takes a better photo, dammit.
I’m the eldest, and in Mom’s baby album, there are tons of pictures of me. Then there is one page with a picture of my sister as a newborn…and after that, the rest of the album is literally blank. My sister is still bitter about it.
(There are tons of photos of both of us; it’s just that after my sister was born, Mom had no time to do things like arrange photos in albums. But that doesn’t stop my sister from being bitter.)
That could be a blessing, my mum has kept even the really bad school portraits of me - ergh.
Dead right! My older brother appears in virtually every picture of me - except the ugly school ones - he’s usually in the background, having just popped out from behind a bit of scenery. I asked mum about it and she reckoned she never knew he was there until the photos got developed. My only-child cousin was the same, we even have a blurred picture of his head where he jack-in-the-boxed up six inches in front of the camera when dad was trying to get a Christmas dinner shot of the rest of us.
I think it happens with grandchildren as well. There are tons of photos of the Diva, partly because she was my folks’ first grandchild, and partly because my sister is organized enough to actually put photos in albums in a timely manner. There are not as many photos of the Princess taken by my folks, but my ex and I made up for it. However, most of them are still in boxes waiting to be put in albums, or, lately, in my computer waiting to be printed. I’m a lousy mom that way. 
As for me and my siblings, there are way more pics of me than of my sisters, 'cause I’m the oldest , nyaah! 
There are plenty of photos of my brother, though, because he is the youngest as well as the BOY, which carries a lot of currency in a Latino family, as you may have gathered.
It wasn’t true in my family (but this would be back in the 1960s). There are only a handful of infant photos of me and of my older brother in existence, but when our little sister was a baby, and we were 2 and 4 respectively, suddenly there are whole albums full of photos available. That was the year Mom and Dad had bought a camera.
and your younger sib?
Sort of the same, here. I was last born of four. There are baby pictures and a modest amount of documentary evidence of my three older siblings, but around the time I was born the photo albums exploded.
I think a big part of this was the advent of cheap 110 cartridge “Instamatic” cameras from Kodak. These were affordable enough to be given to sibs when they came out. (They were aged from 8 - 12 at the time.) I can remember by the mid-seventies we had a big Electrolux naugahyde chest filled with cheap camera gear for six people. Boxes of various film formats, flash cubes, flip-flashes, “extra” cameras from past years, etc.
In 1959, there was one camera in the house - A nice little Zeiss that took 35mm rolls. By the late sixties, I know there were a couple 126 cartridge Kodaks (one was my mom’s and one was my oldest sister’s.) In 1971 everyone in the family except for me had a camera. I had five people to document my every move.