Image Sizing - using Google Images.

A good size image to work with is about 1280px wide and must be a horizontal The height would bebetween 860px and 960px high. You can always get a larger image and resize it. But do not get a smaller image. You cannot make a small image larger without pixelation (blurring/distorting).

If in doubt about image sizing, in Google Images run the mouse over the image you want to use and check it's size. (See the screen shot below). Though it shows greater than 2mp, Google does not always get the image size right!

So you then must run the mouse over the thumbnail image and the size will appear. (See second image below).