Ok, Ozhara, Thank you for your advice. Now I trying to do it

Well - just in case - you can't change it later, just set it when uploading.
So - ifyou ant to stand out a little more from all the other 'blank' mods - I highly suggest to do another upload before you get more visitors and subscribers. :)

It's really simple - before clicking 'publish' - click the button right beside that says 'preview'. This will open an normal windows file dialog to choose your main image.

Hi, Ozhara. Everything is simple - I don't know how I can choose main image ;)

Hi, looks cool and glad you like my terrains. :)

Just a simple question - why didn't you add the preview pic as main image?
I mean there is a 'preview' button right beside the 'publish' button to choose your main image...