Edit post & automatically adding hashtags

hello all

question:
I post my photo in mobility without a lot of time and I never spend enough time to add the hashtag
I am looking a way to automatize an update of my posts adding hashtags based on a list previously provided or based on an auto-tagging of the content within the picture

any help?

When you add hashtags in an update they are not as effective as if you added them as you post the picture.
I don't know how to do want you want to do but maybe that was useful