PC/Windows - Sizing the picture

Right-click the file and select open with then find paint. If paint is not there, select Choose another app.

Select the Home Tab, then choose Rectangular selection from the selection drop-down, then select the part of the picture you want to keep. If you don't like what you selected simply click outside the selection and select again. When you are happy with the selected section, click Crop.

Select the File Tab, then select properties. The box will display the size of the picture. Calculate what percentage you need to expand or reduce the picture to fit the 6" wide and 5 1/4" tall window.

Select the Home Tab, then select Resize and Skew. Ensure the  maintain aspect ratio button and the resize by percentage button is checked. Change the Horizontal box from 100 to what you calculated and the vertical will change with it.  Click OK. Go back to check the size to ensure it is the correct size. If you don't like the new size, click the Undo arrow (back up) at the top of the window or Control-Z to undo the change and try again.