ADDING images to your workshop items

[Gator13 (nosound)]

please make it easier to add images for your workshop items. there is no button or option to use an image as a thumbnail. as you're scrolling through the workshop, you'll see plenty of mods that have no picture on them. but when you're on the mod page there ARE pictures; most likely those people are in the same boat as i am. if you upload one image, that image should automatically be used for both the main image you see when scrolling down a page of mods AND for your mod page.
i understand you need to go into your folders and mess with stuff in order to add a main image for your mod. that's ridiculous. make it easier for people, please.
im not the only complaining about it.

[Mailer]

Is this related to the Steam workshop of "Streets of Rogue"?
One of the developers responded in a thread about this topic, I think:
https://steamcommunity.com/app/512900/discussions/0/1736634807196253619/

Keep in mind, different workshop-supported games do thumbnails differently. For Garry's Mod, for example, it is quasi-mandatory to include a thumbnail.

Having said that, I have always lacked that flexibility of being able to switch out thumbnails on already existing workshop items without having to update them. I assume the only reason this isn't possible from the workshop item edit page directly is because of server limitations or something like that.