Two lanes but 3 traffic signs. Is the middle lane hidden?
Information concealment is one of the techniques to hide important content. There are many tools that comes with steganographic processing. Usually, media files are chosen as the host file to store the secret data but their native usage (viewing photo, watching video with associated apps) are unaffected even with secret data injected. Media files are the popular host because photo, audio or video are basically having larger size. The objective is let secret message stored there and staying low profile without being caught.
Yet, this technique is aimed at hiding small amount of data (like passcode, geo-location) because too much data might increase the host size that is unproportionable to its original form.