Praise be to Allah.
The Lawgiver has made it permissible for the suitor to look at the woman to whom he wants to propose, because there is an interest to be served by that. The basic principle is that he should look at her in real life, not look at her picture, because the interest to be served has to do with looking, which cannot be done properly except by looking at the woman in real life, and because a picture does not usually show reality.
But sometimes it may not be possible for the suitor to look at the woman, so he needs to look at her picture, so that by looking at her picture he may get a general impression, that could help him to decide initially whether to go ahead or not, so that when he is able to look at her after that, he may decide to go ahead with the proposal or not.
So if the suitor needs to look at the woman to whom he wants to propose, and he can only do that by looking at her picture, and he is serious in his intention to propose, then there is nothing wrong with it, as it serves an important purpose. But that is subject to conditions that we have mentioned in the answer to question no. 132499 , one of which is that what appears in the picture should be the face and hands, and what would normally be uncovered in front of her mahrams, such as the head and neck; another condition is that his seeing the picture should be through a trustworthy intermediary, and the suitor should not keep this picture or show it to anyone else.
If the conditions referred to were met, then there is nothing wrong with what you did, in sha Allah.
If he changed his mind about this proposal, it is not permissible for him to keep this picture or to make any copies of it, and she should give it back to her friend or to the intermediary through whom she received it.
And Allah knows best.