I have found the simplest way to make pictures fit is:

1.go to your pictures folder
2.open your picture ... it will open with your picture viewer
3.then click on 'open'....open using 'Paint'
4.once you have it opened in 'Paint'
5.click resize.....and I generally shrink them down to 20% of original....
6.then just click 'save'
Done!