My sister is jealous that my niece looks like me

So, my niece is my spitting image. 
Seriously, when I look at that child I see myself and it almost weirds me out. The only difference is that her hair is lighter than mine. At first I never said anything about it, she came out looking like i birthed her, our baby pictures are identical. I didn't say anything because I knew my sister would feel some sort of way about it. 
Our family and HER family seeing as we are half sisters (which makes the fact that this child resembles me so much wierder) has said it a million and ten times how much she looks like her aunt, the older members of our families call this baby by my name on accident. At first my sister was like "eh" but now I think she notices it too. Everytime someone says it she gets this hateful look on her face and it's like she's started to resent me. People will comment on her Facebook pictures about how she's MY mini me. My sister either deletes the comment or just doesn't respond. Like, I am sorry. I did not choose for your child to resemble me. It's not my fault so I don't see the reason to resent me.. I don't know what else to say to her.. I don't want her to resent me forever and I completely understand her jealousy.. I mean who wants their child coming out looking like their sibling? Nobody. I don't know what to do:/