If you don't know how to make GIF's, then refer to my GIF Tutorial. To be able to do this you need some knowledge on Photoshop and GIF making. I won't be teaching you everything about GIF's in this tutorial as you will have to read my previous tutorial.
(CLICK IMAGES TO MAKE THEM BIGGER!)
Open your image and make sure it's the right size!
Okay, so now you should have something like this...
Okay, now select the first and last frame only, making sure the one in the middle isn't selected. Then on the right in the layers box, click the picture of the eye on the duplicated layer so that it doesn't have the eye showing on that layer any more.
Now for the step that creates that vibrating look. Click the second frame (the middle frame). And make sure that the second layer on the right (the top layer) is selected. Then go to Filter > Blur > Motion Blur.
The Motion Blur box should pop up. Put in a number around about 10 to give it a decent blur. You can have whatever number you like to make it look the way you want. But I usually go for 10.
Select the first and last frames and click the small arrow with the timing at the bottom of the frame boxes. Then select a timing around "0.5".
Now do the same for the second/middle frame but select a timing for "0.1". This is so it doesn't last a long time. Having a quicker speed for the vibration gives it that nice subtle effect.
Then if you want to, add a new layer on top of the rest of the layers and add your watermark! I always do this.
Now you're finished! Now go to Save For Web and Devices for your GIF. (If you don't know how to do that, go to my previous tutorial on how to make GIFS. Hope this helped you guys out! <3
This is how mine turned out! And yours should do too!