Selecting one image of several as thumbnail
In some cases parts have several images. If this is the case, and one of these images shall be used as thumbnail in the overview, the image to be used in the overview needs to be selected.
From version 5.1 this function is discontinued and replaced by sequence number on image.
Step-by-step guide
Follow this procedure to mark an image as thumbnail image in gallery
Open image repository
Find the image to be used in the gallery as thumbnail and select the image
Add a Category "Thumbnail" on the image
This will make the image to be selected as thumbnail.
If several images are marked as thumbnail the selection will be undefined.