It's probably too big, some camera take pictures that are over 30 inches, a good size is around 8 inches, you don't have to make them really small like some people do. Here's a site that offers free resizing.
Free Online Picture Resizer - Crop and Resize photos, images, or pictures online for FREE! If you use this site, pick 800 pixels for the largest side is about right, or you can just do percentages.