How do I change the size or format of a picture?

My pictures on my computer are in JPEG format, and the smallest one I have is 1.11 mbs. but most of them are 2.something. but i don't even know what that means. I need to change a photo to get it on a website, could someone please tell me how?How do I change the size or format of a picture?
You need a type of photo software like photoshop. Perhaps if you have a default photo software like paint or something you could open it in that program and see if you can change the size.



First find out what your program is that your computer uses to view photos. Then you have to see if you can access the help button to see how to re-size a picture.