Each time we take a picture from a digital camera or smart phone, the exif tag and other photographic meta data are include in these pictures. These meta data contain info about your camera or your phone, GPS location,... To protects your privacy or reduce the picture size before publish the pictures on the web, you should remove exif data.
On Ubuntu: Using GPS Correlate
In the terminal:
To show the exif tags: gpscorrelate -s *.jpg
To remove the exif tag: gpscorrelate -r *.jpg
On Windows: Using a free software called IrfanView