Hi George, and welcome!
There are a lot of options for reducing the file size of digital pictures. You can reduce the physical size of the picture and you can reduce the resolution and the quality; all of these will reduce the file size.
And there are many programs, many free, that will do these things.
Tom outlined a method using Paint, which comes with Windows. My version of Windows also came with Imaging For Windows. Start`Accessories`Imaging. I really don't care for the program, but you can use it do reduce file size. In fact opening a jpg in Imaging and then saving it will reduce the size. But to further manipulate the size of the image in Imaging, right click on the image and choose Properties. The tabs for Compression, Resolution and Size all offer choices for changing the size. The program seems a little quirky, but should be of some help if it's on your computer already.
My favorite little graphics program is
IrfanView. I use it not only to change image sizes, but also to easily and quickly touch up pictures that are too dark or have other problems.