If you are using photo designing tools like Photoshop to create JPG Images for your web development, Usage of such softwares will increase memory sizes of the images being generated
Some excess datas being stored are
  • Texts such as
    • File written by Adobe Photoshop
    • Creator: PolyViewĀ® Version 3.32 by Polybytes, LEAD Technologies Inc. V1.01
    • Created with GIMP
  • Picture previews/thumbnails (sometimes even bigger than main JPG data!)
  • Color Management data – RGB/GrayScale, 8/16 bit, SRGB/LinearLight
All this data is useful only when opening the file in program that is used to created it.

Other programs such as Internet Browsers will just skip this data, so the data is downloaded and then threw away!

So,before publishing JPG files on the internet use this program to remove such extra stuff to make JPG files smaller without quality loss.

I tried and it really works