Wp Foto theme is single layout theme designed for photo blogger. It uses custom fields for displaying thumbnail in home page, archive page, category and tag page.
Create 100 px width and 58 px height image for thumbnail and create a new key under Custom field titled thumbnail. And paste the url of your thumbnail photo.
Wp Foto Theme displays only one post in front page. If you want to show more than one post, you can customize it. To change, find the following code define(MAX_PHOTOS,1) in index.php and change the number 1 to any you want.