Over stepping sister

My sister is quite annoying. She will do anything for attention. She has posted our gender reveal, our pregnancy announcements, our birth story, EVERYTHING that is personal for my husband and I to share, she shares. And I'm not just saying she directly shares it. I'm saying she will save our picture and post it as her own.

So my son turns two tomorrow, she just posted in his fb party invite thing I have going how shes going through all her pictures to make him a birthday collage for tomorrow for her to post 🥴

This just irritates me SO much!!! 1. He's turning two, he's not going to care or understand her stupid little post. 2. She's the aunt he doesn't even care for lol. He absolutely loves my other sister, and wants nothing to do with this sister. Probably because she never comes around. 3. That's something that the PARENTS get to share. Like that's my husband and I's moment. I don't know how anyone could honestly take something like that from the parents. Like it just bothers me, mainly i guess because I know she's doing it for her own personal gain.

I just honestly don't know what or how to go about saying anything to her without coming off as a bitch. Which I've kinda been calling her out on her bullshit a lot lately 🙃 and don't really want to add more fuel to our fire already ya know?

*before everyone starts assuming I'm just going to come off harsh lol 🙄 my sister is OVERLY sensitive, she hates confrontation. So even if I am nice, but say something to her, I'm the bad guy. I could put it in the nicest most sweetest way possible but because I'm confronting her she will cry to my mom about how mean I am.