Free: Contests & Raffles.
If you have Microsoft Office on your computer you should have Microsoft Picture Manager. You can use that program to resize. Try going with a size of 800x600. Go to the "Picture" drop down menu, select "resize", and then use the 800x600 size under "predefined width and height".
You can also use this site. Real easy to use. If you just select 800x600 it's more than likely going to distort your pic. I use this tool and just select 75% and resize. Easy and works great.http://www.picresize.com/