No, to push your buttons.

Next time she takes these pictures, your DH needs to say - "Hang on, let's wait for SeeYouNever to get back from the bathroom," and walk away.  He's being much too passive about how his sister treats you (caveat - she is allowed to take some of just him and SD or just him or just SD, just not to make a point to exclude you). 

This is all on your DH. I would refuse to go & REFUSE TO ALLOW MY CHILDREN TO GO to another event. After all, your not even in your immediate family photos. Your children & step children see you being marginalized, even your DH thinks you aren't important enough to be in the photos. 

But in my husbands family its a little more subtle. We went to a wedding and yeah, photos were taken of the smaller families, and DH and I did our thing. But I now think back and notice the spouses are on the "outside" and the women/mothers are the inside section (crop!crop! crop!)

And Im in a group chat. No one EVER likes or anything when I send through a photo of just us two. Its just ALL about THEM, and its ALL the time.

I would have a chat with your husband, so he can stand up to his sister about this.

My husbnads neice did this at her gender reveal and her baby shower. I didn't say anything after the gender reveal but after the shower I did say something to DH becuase it did hurt my feeleings. He of course was clueless that day and didnt notice but he did say he would make sure it doesnt happen again. He is very passive at times though so only time will tell if he will remember and make sure I am included in some photos at future gatherings.

And thats what kills me - Even if the neice didnt want to keep photos of her shower with me in them she could have taken some with me in them and some without. It's not like they will be framed and going on her living room wall! I take pics of SD and DH (for ex when he had his bday and then a week later she had her bday), I take them for DH to have not for me to keep. 

(Oh the divorce photo comment - HA! One Christmas DH, SD and I took a photo in front of a pretty tree. I made sure SD was on the one side of Dh and I cropped her out of it and have the pic of just DH and I in one of my photo albums!)

((HUGS))) I know you are upset. She is a jerk. I am being polite

Give yourself some time. Before you know it you will say SCREW this s*** I am not going anywhere those people are. I would say to dh, GO ahead darling DH, you go...here is my plate of cookies to give as a house warming gift. 

-------------

When ever I read here about picture drama, it reminds me of BM.

Several years ago There was a protective order against BM, long standing one too. She was ordered to NOT be around her 3rd husband's child, HER own step child period, no matter what the circumstances. The order was for very good reasons and not a jilted x wife bs. That skids bio dad is The old boyfriend of  BM. BM and he go back years and years. BM married HIM after my dh and she divorced ---another story in it'self.

ANYWAY

There was a picnic or something the step child was attending with her dad during HIS supervised visitation. GO figure, right? BM shows up and stands for photos with the step child SHE was court ordered to stay away from. BM got copies made. BM is smiling ear to ear,,standing an arm length or two away from the kid. BM mailed the pictures to the bio mom and wrote I THOUGHT YOU WOULD WANT TO HAVE THESE pic's of childsname.

HOLY COW--I will never forget that call I got from the skids mom. Of course nothing was done about it..bm said she forgot about the protection order or something along those lines...opppsee she made a mistake. Knowing what I knew about bm then, I was not surprised she had the nerve to upset this very nice mom. 

Your sil is taunting you OP...and I am sorry. Maybe consider not going to those events, is that something you can do? You know the outcome,,,it usually is very hurtful.

(((HUGS)))

This is some next level passive aggression on her part. Maybe your DH should make snarky comment along the lines of, "SIL, why do you always insist upon taking photos when SeeYouNever isn't here?" and then laugh and walk away while her face turns red. Or start to take his own photos at events that include SIL partially cut out or are completely unflattering to her...like in the middle of eating. 

"SIL, I would LOVE some photos with my own kids. Do you mind snapping a few?"

Sounds like you've got one of those slightly warped, inappropriately territorial SILs. I have one, too. They tend grow in families that have poor/no boundaries, with parents who don't correct unhealthy behavior. There's usually a clueless/passive DH in the mix, who often can't see the bs because he grew up around it. The result is grown women who stomp boundaries, target "outsiders" and play high school mean girl games.

Use the ST search engine to check out the blogs and forum posts of members jcksjj and Disillusioned. The latter has been dealing with a vicious triangulating SIL for over twenty years.  Google Relational Aggression, and learn everything you can about it. Two key points to understand? Firstly, it isn't personal or about YOU. These *itches simply do what they do and would target ANY female new to the family group. Secondly,  how your H reacts to the aggression is crucial. If he isn't willing to:

Acknowledge what is happening

Operate as a team

Protect you

Draw boundaries

Put his sister in check,

then your options are limited, and should include counseling.

Lastly, I have to wonder how things might have gone if, all those years ago,  I had just looked my SIL in the eye and said "I've noticed you do A, B, and C when I'm around. Why do you think that is?" Sometimes the direct approach is the most powerful, so perhaps consider that as well.