All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
If this dress covers parts of the body that you must cover in front of this woman, and you are sure that this woman will not allow a non-Mahram man to see your picture, then it is permissible for you to send it to her.
If any of these conditions are not met, then it is not permissible for you to send it to her.
Allah knows best.