how to decrease jpg size/image size/picture size?

There are some ways to decrease image,jpg,picture size.The best one is to using format factory software.to do this use following steps.
#download and install format factory in your computer from this link 
#open format factory software >click Picture option in left site of format factory window.>click All to Jpg
just like this

 

#click> output setting>click>max height and max width>click ok>click>add file>browse jpg or picture which you want to decrease size.

#Finally go to out put folder of format factory.