Change the kinds of lots in CSS City or make your own, try them in the city on the right, then download your city: one HTML file that runs on CSS alone, no JavaScript.
Each design keeps its own lot types, pictures, roads and placed lots, and saves as you work.
Others can open your design and use it as a starting point. A link holds the whole design (no server needed); designs with uploaded pictures are usually too big for a link, so save those to a file (a .zip with the pictures in it).
Changes show up in the city right away. Lots repeat their edge drawings, trees and stretching buildings as many times as fit, so a lot fills in as its roads make it bigger.
Upload pictures to use on your lots: PNG, JPG, GIF, WebP or SVG, up to 300 KB each. Drawings in the same isometric style as the city look best. Uploads stay in this browser and are built into the city you download.
Drag roads and place lots in the preview. They stay put while you change the lot types.