3/. Image sizes
There is a minimum image size to work with and that is 480px wide.
Do not user smaller images, as you cannot make them larger without pixelation.
Think about the page titles and what sort of images you would like to include.
DO NOT copy/paste images in. They will not work.
Image sizes. DO NOT use the small thumbnail sized images.
The bigger the better, for you can always make a large image smaller, but NEVER a small image larger (as it will pixelate - become blurred).
In your research in Google, use the following image search commands:

Image Widths adjusted for your webpage. This is a task in itself well worth learning.
To do this you will use Photoshop to either resize the images or crop them.
See the two ways of doing this linked here.
Image sizes are really important, so this preliminary step is most important to complete before building your webpages.