I just don't think it's really well-thought-out critique.
I am reading, at this moment, a biography of Empress Elizabeth of Austria. She has what is clearly visible to modern eyes as an eating disorder, and she is constantly stressed and paranoid about her looks, because she has come to understand that it's more or less the only weapon a woman has.
Women have come a long way since Elizabeth's time, but the culture of obsessing over our beauty hasn't really quite caught up. How many "normal looking" women do you see on TV vs. "normal looking" men? How many perfectly average female comedians build entire bits around the fact that they're hideous?
Elizabeth never let photographs be taken of her past the age of thirty, because she was terrified that the existence of proof of her aging (which was minimal; she was a renowned beauty til the day she died) would rob her of power and besmirch her legacy. She posed for intimate portraits that featured her bare arms and carefully-staged masses of her dark hair, which was inordinately proud of. This follows a grand tradition of everyone with sufficient money commissioning portrait painters who depicted them surrounded with all their wealth and prestige; people'd literally stand for hours a day so a court painter would show future generations how great their shoes were. By comparison, taking five minutes to pose a really great butt shot and send it over snapchat seems pretty trivial.
I love that women are capturing their likenesses. I have a crippling fear of having my photo taken because I so desperately hate the way I look and I wish I didn't; I wish I had the confidence to go take a picture of my ass, to be quite honest. Women are stuck between a rock and a hard place where they have to be beautiful but also can't be vain, and fuck that! I'm for one glad to see a culture of reclaiming it.
You say yourself that you love a beautiful woman but you don't want your SO to be so "narcissistic" that she has to catalog that beauty. Why? Maybe she appreciates being beautiful too. Maybe she wants proof of it to look back on when it's faded because she, too, loves a beautiful woman, and that beautiful woman was her. My grandma kept a photo of her homecoming dance on proud display in the middle of her living room til the day she died and visitors would gather around to look at it and exclaim over how pretty she was back then. And she liked that, as well she might.
This movement of female culture towards selfie-taken serves two purposes: to reclaim their own image and ability to look like they do (to document "normal looking" women and recognize that they too have worth), and to document their own beauty and be as proud of it as society suggests they ought to be. These are sometimes in conflict but that's a necessary thing--expectations are messy and so is culture. I'm fine with the two co-existing; they both serve valuable purposes.
I also hate this "instead of living" narrative. I have horrible memory problems and I used to have to write down setlists and take notes during concerts and shows I saw in order to remember them. Now I'm one of those assholes who's getting her phone out every fifteen minutes to jot down the setlist and snap a photo or a short video. I won't remember them otherwise. People have been documenting their lives both for the sake of curating them for others' consumption and for their own sake for literally as long as documentation has existed, we just have more efficient tools for it now. I reckon the first guy to chalk a giant buffalo onto a wall after a hunt was made fun of for not having a big slice of steak from it instead of commemorating its defeat.