Creating a simple Cinemagraph

So you've shot your video, not forgetting to put the camera on a tripod and switched the AF off.  Now you'll need to load it into Photoshop.  File > import video frames to layers. Locate your video you wish to import and click 'Load'.

Depending on which version of Photoshop you have, you will now be able to select the portion of video you wish to import using the arrow points on the scale bar underneath the video window.  Sliding these back and fore will allow you to choose the start point and the end point. Press OK

Thi   This will load the video as a series of layers in Photoshop.  Click ‘window > animation or window >Timeline in CS6

 In CS3/4/5 you will need to click the icon in the bottom right of the ‘Animations Frame’ window to access the ‘Convert to timeline animation’ or in the top right in CS6

The Timeline enables you to edit the frames further by sliding the pointers to the start position and the end position 

IMPORTANT.  Next, press the short cut key to select the image 'Ctl + A'.  Now copy the image and paste it back, short cut keys 'Ctl+ C' the 'Ctl+V' 
Next, press 'Q' on the keyboard to enter the quick mask mode and with your brush set to 100% opacity and 100% fill paint the area/s that you don't want to move.

Press 'Q' again to exit the quick mask mode and you will see the 'marching ants' around your selection.

Now this bit is really important.  Hold down the 'Alt' key and click the 'Add layer mask' icon in the layers palette (see above).  This will add the vector mask to the layer.

This layer now needs to be placed at the top of the layer pile as shown.  Don't forget you may have a hundred layers so make sure it is right at the top and not positioned somewhere inbetween.

 Now select all the images in your timeline.  Hold the 'Shift' key down and select the first and last image.

Click the icon in the upper right of your timeline window and select 'copy frames'

Do the same again and this time click 'paste frames'.

 Select 'paste after selection'

Once more and this time choose 'reverse frames'.  Now reversing the frames will give you a seamless motion, but do bear in mind that it doesen't work for every cinemagraph.
Make sure that 'forever' is selected in the option menu at the bottom left of the timeline.  You can now test your cinemagraph to make sure it is working fine.

As the project stands it is too big a file so you will need to change the image size as we would a normal picture.  Go to 'image>imagesize'

In the 'document size' change the size of the image.  this example has been resized to 6 inch by 10.5 inch approx. The DPI has not been changed

The image size is reduced

To save the image as a GIF file (so it will run in a browser' we go to File and then 'save for web and devices'

In this window we can change the file size to something manageable.  You can either
choose the height and width in pixels or just change the percentage as shown. Make sure
the looping option is set to 'forever'
Now save.
If all has been succesful it should look something like this 
A last word of caution.  This guide is only a very simple approach to creating
cinemagraphs, more artistic effects can be achieved in the video post production before
it is loaded into Photoshop. Lastly, sometimes, for reasons unknown to me, 
it simply just doesn't work, especially if you've made a simple mistake during 
the process and it then become unretrievable.  My best advice is just start again.

Have fun