To reduce the picture�s size I suggest this small and free program, called, irfanview
http://www.irfanview.com/
Once installed, launch it and open, through the program, the picture you need to resize, clicking on the small folder under "File"

Now select �Image� and then �Resize/Resample�

In the new window select a custom size or use the size presets on the right (like 640 X 480)

Now select �File� (top left) and �save as�. Change the name of the picture (so you�ll not modify the original) and save it wherever you want

Just check that the bar on the right panel is on �best�, so you�ll not loose quality, and that it is a JPG file, for maximum compatibility.