I'm wonder how to recover the original name of picture which was made by device (for example Camera or phone)? Is it possible? Let's say that someone make a photo and then change name of the .JPG file from 20110126_NX003.JPG to sunny_day.JPG. Is it possible to find this original name given by the device if we have only this sunny_day.JPG file?
Experimentally I can't find any reference to the file name in the JPG picture files either from my Canon 70D camera or my smartphone.
Not surprising since a filename is just a label on things.
However, pictures from my phone are named using a timestamp:
And this matches two fields in the EXIF data:
5) DateTimeOriginal = 2018:12:24 18:16:01 6) CreateDate = 2018:12:24 18:16:01
But the last digits (
856) don't match other EXIF data:
17) SubSecTime = 918503 18) SubSecTimeOriginal = 918503 19) SubSecTimeDigitized = 918503
So this may not be sufficient to retrieve the full file name, but enough to know at what time the picture was taken, if this is what you wanted the initial filename for.
Whatever your OS, there are many tools around to view EXIF data, this is normally part of any image viewer worth its salt.
The original filename is not stored in Exif. However, Exif data may be used to reconstruct the filename. For instance, some devices name files according to date/time.
Also, some cameras store a frame number from which the filename can be guessed if filename numbering was set to continuous. If filename numbering was set to reset, the filename may be recoverable by examination of the filesystem journal, but that is way outside the scope of photography.SE.