Frankly, you DON'T hack an Instagram account to view private photos.
They're private for a reason. I think you need to really look at your motives for hacking and seeking to look at prohibited images. What is your reason?
Is it just simple curiosity that makes you want to do this? If you're interested in other people's lives, you should maybe start reading autobiographies,, which are written by people who want to share the details of their lives with complete strangers.
Do you want to look for pictures that will turn you on? How did it come to this? If this is you motivation, you need to learn something about consent and objectification. The people in those photos have not consented to you objectification of them.
Are you looking for evidence of a betrayal or proof that someone you once loved no longer loves you? Be kind to yourself and don't go rooting through data that does not belong to you.