It's a unique ID that every image/video has. Renaming the file is enough to change it, you have to crop or use a MD5 hash changer. If you don't change it, then Instagram knows you duplicate content and that's how you can get banned.
You can automatically change the MD5 with Jarvee
Go to Campaigns > Your campaign > Overview > Tick "Make images unique before they are posted". Small is enough
