Is your Samsung phone showing “Storage Full”, and when you check, Facebook is using several GBs of space? You’re not imagining it. The Facebook app is one of the biggest hidden storage eaters on Samsung phones, especially on Galaxy S21, S22, S23, S24, and S25 Ultra. Even if you don’t download videos manually, Facebook quietly stores cached videos, images, stories, and background data, which slowly fills your internal storage. In this guide, you’ll learn why Facebook causes storage issues and how to fix it permanently.