If no image is available a default image is used.
You can sort the images on any column(s) to display the thumbnails in the order you want.
You can set the size of the images in preferences. You can also scale the images dynamically. If you want to see more images without scrolling you can shrink the images so that more will fit in the window.
If you hold the mouse over an image a popup window is displayed with information on that item. You can define the format of the popup, what columns are included etc.