@B Kahn I don't think there is, @dansup is the developer, so he could answer that one, but I think its only mobile clients as that's the typical model for a product like this, but you could always upload through the web site:
That's what it looks like for me using FireFox on Linux. Far as I know loops.video is doing sign up and I think there are other instances, or you could spin your own up if'n you're inclined.
So someone posted their favorite sign over on Mastodon, and I replied with what is my favorite sign, the 'No Straight' sign.
First time I saw this was on a new intersection where one side is a highway ramp, and the other a two-way road, apparently 'Do Not Enter' signs weren't enough, so they put one of these up. Honestly, I'm surprised to know its a standard, Missouri isn't exactly known for sticking to standards, whether its abbreviations like LA for lane, or the non-standard all text signs on the road to my house announcing the road closure ahead and the truck ban on it.
