Migrating your Instagram photos to your Dropbox account is easy using PicBackMan tool.
Here’s how to migrate Instagram photos to Dropbox
Note that PHOTO and VIDEO upload shouldn’t be running. Also, it might take time for migration to complete depending on a number of photos you have in your Instagram account.
Here’s the video tutorial you can refer to
PicBackMan is a free photo/video uploader that helps you to keep your memories backed up to your favorite online services.
Users in 130+ countries have backed up.
... an excellent job of uploading more then 300GB of photos to 2 different services