brick,
We would also like to welcome you to the John Wayne Message Board!
If you don't already have software on your computer that will allow you to resize your photo, there are web sites that offer that service, for free. HERE is one example of such a place. You can do a Google search for "free photo resize" and see other results.
Once the photo is an appropriate size, just follow Keith's directions (the Mrs. says she finds it helpful to print out the directions, so you can follow them more easily, step by step, while you are doing your task).
Again, WELCOME, and we hope our suggestions have been helpful to you. We look forward to seeing your picture, and hopefully there will be some folks who can assist you in dating it.
Chester 
and the Mrs. 
