If you're not familiar with metadata, go to Metadata.
You may want to remove metadata to prevent someone from learning sensitive information about you.
For example, let's say you're photographing in a school.
Your camera may record the location of the photographs, and therefore, the school.
You would probably want to remove the metadata from copies of the files if the photographs were to be posted on the Internet.
Remove the metadata from a copy of the file.
Then, you can always access the metadata from the original file.
When you're using Photoshop or Photoshop Elements, save the file using Save for Web.
The metadata is removed to reduce the file size for faster page loading.
You can use IrfanView, a free editing program, with the Lossless JPG Transformations plug-in.
If you know what command line means, then you know a lot about computers.
You may prefer the program below.