Cinemagraph guide

Start

The tool opens with a lake sample at 800 × 600. Its water is already painted, and the line under Image reads Sample 800 × 600.

A current browser with WebGL 2. Chrome, Edge, Firefox and Safari all have it.
A photo, if you want your own. Any picture the browser can open works. Photos with something that naturally moves, such as water, sky, hair or smoke, work best.

Open Cinemagraph. The sample water is already moving.
Press Image A to open a photo, or drop one on the frame. Or keep the sample and skip to step 4.
With Paint chosen under Brush, drag over the part that should move. With a mouse or a finger, the paint follows your drag. Switch to Erase and drag to take some back.
Under Animation, pick an effect such as Flow or Wave, and raise Amplitude until the motion is easy to see.
Press Record video at the top of the panel, Save frame or Copy.

A new photo starts with an empty mask; nothing moves until you paint.
Show mask tints the painted part blue so you can see it. The tint is only on screen: videos, Save frame and Copy leave it out.
Paint builds up: going over the same place again makes it move more, up to full.
Sliders glide to their new value over a few frames, so the motion changes smoothly while you drag them. Speeds are rounded so each effect repeats a whole number of times in every loop, so a speed can change in small steps.
Your photo is kept on this device, and every lab tool that takes a picture opens with it, until you press × on its tile. The mask you paint is not kept: a photo that opens the page starts with none.
On a phone the controls sit in a bar at the bottom of the screen. Tap the bar to open them. Dragging a finger on the photo paints; it does not scroll the page.