Virto Thumbnail View Settings
Once you have installed the solution to your SharePoint site, you need to adjust it according to your needs. Go to “Library – Library Settings” and find “Virto Thumbnail View Settings”.
Here you can define default width and height of images in the slideshow mode and allow thumbnails instead of icons displayed by default. Just activate checkbox “Show Thumbnails” and enter width and height in pixels.
Click “Save” to save the settings and return to the library.