The description text for a mod I made, from the _metadata file, displays at the bottom of the text instead of at the top; so you have to scroll up to get to the start of the description. Why is this? If I click away from that mod onto another and back again it again starts from the bottom. Also, I've noticed other mod authors include a preview.png image or _previewimage file. I made one for my mod but these images aren't even used in the game so what's the point of making one?
So how do you use them? I've tried both preview.png and _previewimage and neither appear in Workshop. I had to add a picture instead to my mods page.
When you use the upload mod tool, it asks you to select a preview image. That will generate the _previewimage file and upload it to the workshop. Note that this is not the image(s) that you use to show off your mod, rather it is just an icon that people will see when scrolling through the list of mods.