'A Cinemagraph is an image that contains within itself a living moment that allows a glimpse of time to be experienced and preserved endlessly.'
- cinemagraphs.com

'Cinemagraphs are still photographs in which a minor and repeated movement occurs. Cinemagraphs, which are usually published in an animated GIF format, can give the illusion that the viewer is watching a video.'
- Wikipedia

Look for more examples on these websites:
http://cinemagraphs.com
http://cinemagraphcollection.com
http://www.reddit.com/r/cinemagraphs

Step 1: Open a Video File

Open a video file.

A few requirements:
- Everything in the video should be as motionless as possible, only the thing you want to move has to move
- The video can be looped
- Choose a small file

Go to document settings and change the fps (frames per second) in 15.

Step 2: Select a Work Area

Search with the Current TIme Indicator for a starting point of the cinemagraph.

Grab the blue select tool on the left side, near tot the Current Time Indicator, hold Shift and move to the Current Time Indicator. The area that's colored grey now is the part of the video you don't use.

Select about 12 frames by clicking 12 times on the Select Next Frame button.

Grab the blue select tool on the right side, near tot the Current Time Indicator, hold Shift and move to the Current Time Indicator. The area that's colored grey now is the part of the video you don't use.

Step 3: Freeze the Video

Go to 'Trim Document Duration to Work Area'. Now the work area you selected is left.

Go to Select > All.

Edit > Copy Merged.

Edit > Paste.

To see your layers go to View > Layers.

Now you have two layers. The first layer is the video, the second layer is the image you pasted.

Step 4: Select With the Quick Mask Mode

Select the Quick Mask Mode.

Use your brush to select the area in the video that shouldn't move. Leave the moving part unselected!
For example: in my video I want the tuft of hair move, the rest I will select. The red area is selected.

Zoom in to get the selection perfect.

Unmask the selection by clicking on the Quick Mask Mode. A selection area appears. Delete this selection by clicking on the delete button on your keyboard.

Step 5: Create a Frame Animation

Click 'Flatten Frames into Layers'. A list of layers appears, the cinemagraph will be made out of these layers.

You now have to delete the video layer.

Click on Convert to Frame Animation.
One frame appears.

Click 'Make Frames from Layers' to add the layers to the frame animation.

Step 6: Make It a Working GIF

Change the time duration of the first frame into No Delay. The time duration of the other frames are automatically set correctly.

Change the loop into Forever. It means it will loop forever.

Click on the play button to play the GIF.