There are hundreds of photo editing software packages out there. Most come free and already installed on the computer when you buy it. Microsoft Photo Editor is an example. Another is Adobe Photoshop, free at http://www.adobe.com
In Microsoft Photo Editor, you load the picture, click on “Image” and then “Resize”. Change the 100% field to something smaller like 80%. Save it and give it another try. If it’s still too big, drop it another 20%. You can right click on the photo and click properties. The file size will show there. It needs to be smaller them 100,000bytes, or 100kb.
In Adobe, you use the “Crop” function.
Keep trying. The first time is always the hardest.