Sometimes I experience that a image files date/time on the file system differ from the image metadata/EXIF info.
I use this command to extract the date information available in the file
$ exiftool -time:all -a -G0:1 -s filename.jpg
The output from the command can be like
[File:System] FileModifyDate : 2016:06:08 14:40:24+02:00 [File:System] FileAccessDate : 2016:09:01 23:39:40+02:00 [File:System] FileInodeChangeDate : 2016:09:01 23:39:17+02:00 [EXIF:GPS] GPSDateStamp : 2015:07:28 [EXIF:GPS] GPSTimeStamp : 14:46:47 [EXIF:IFD0] ModifyDate : 2015:07:28 16:47:09 [EXIF:ExifIFD] CreateDate : 2015:07:28 16:47:09 [EXIF:ExifIFD] SubSecTime : 426 [EXIF:ExifIFD] DateTimeOriginal : 2015:07:28 16:47:09 [EXIF:ExifIFD] SubSecTimeDigitized : 426 [EXIF:ExifIFD] SubSecTimeOriginal : 426 [Composite] GPSDateTime : 2015:07:28 14:46:47Z [Composite] SubSecCreateDate : 2015:07:28 16:47:09.426 [Composite] SubSecDateTimeOriginal : 2015:07:28 16:47:09.426 [Composite] SubSecModifyDate : 2015:07:28 16:47:09.426
This can give a lot of info about the original date/time of the file.
We can now decide to modify a files FileModifyDate with the info from DateTimeOriginal
$ exiftool "-filemodifydate<datetimeoriginal" filename.jpg
Source: http://www.sno.phy.queensu.ca/~phil/exiftool/faq.html#Q24