HowTo/Bridge/image
From TrainzOnline
image
This is a required tag.
Data type is string.
This is the name of the image file to be displayed. By convention the first image is normally the one to be displayed in surveyor and is called "thumbnail.jpg". It's size is 240 pixels wide by 180 pixels high. It can be any name but it has become a unwritten standard to use "thumbnail" as the first part of the file name and then the relevant image type extension.