Every camera adds so called metadata to your images; it contains information like resolution, ISO-Speed, aperture time, etc. Depening on your camera model even the serial numbers of your camera and/or objective are being added.

Because of that you should either remove all the metadata or just parts of it.

See also Photography.

To remove metadata from your images you can use the following programs on Linux:

• exiv2
• exiftool

The manpage of exiftool warns to not remove metadata from raw files as those information may be neccessary to process the files. Only remove metadata from (copied) files you want to upload.

On Windows you may use Exiv-Tag-Remover.

• Remove all metadata from images
• Remove only some meta data from images

exiv2 rm *.jpg

See man exiv2 for more information.

exiftool -all= *.jpg

See 'man exiftool' for more information.