There are certainly many ways to re-size available. I came across "Quick Image Resizer" a couple a years ago and was one the better software programs I have purchased. The icon sits on your desktop. You open it and drag the photo you want to re-size into on open blank area where it's automatically re-sized to blog, thumbnail, small, med, lrg. and xrta lg., whatever you select. It gives you the file size immediately so you can re-select if you need. I use it all the time for emails; it's super handy. Just one you might consider. Happy shooting.
http://www.dzsoft.com/image-resizer.html