It is not permissible to keep pictures of animate beings for memories. This has been discussed in the answer to question no. 10668.
There is no sin on you if your sisters and aunts keep these pictures, but you have to explain the shar’i ruling to them and advise them to get rid of them. You should ask them for the pictures that they have of you, but if they refuse there is no sin on you.
With regard to pictures on cell phones, computers and videos, these do not come under the same ruling as photographs, because they are not tangible, unless they are printed. Based on that, there is nothing wrong with keeping them on the cell phone, so long as they do not include anything haraam, such as if they are pictures of women.
See also question no. 10326
And Allaah knows best.