We are going to attempt and create an animated shine and we are going to need a shiny object. Open the picture in Photoshop and then create a new layer Layer-New Layer and name it Shine.

Using the Polygonal Lasso Tool draw a rectangle across the picture as shown and then create a new layer Layer-New Layer and then select a white foreground.

Select the Gradient Tool and then click on the Gradient icon to select the gradient in the orange square and then click OK.

Make your gradient by drawing a line from right to left and then reduce the layers opacity to 30 to 40 % if necesary and then click Select-Deselect.

Now click on the layer that has the picture to select it and then use Magic Wand while holding Shift to select the areas where you want to see your shine reflected. I clicked the shiny areas of my picture.

Now select the layer named Shine and with it selected, click the icon to add a Layer Mask. After you do that, the shine layer will have a little Chain in the middle. Click on it to get rid of it so that the two layers are no longer linked together and we can move the shine by itself. Save your work and now we go to Image Ready.

Select the Shine Layer and use the Move Tool to move the Shine to the beginning of the document. Click on the Icon shown in the picture to take the first frame.

Now move the shine all the way to the right and you are going to click on the tween tool now. When the next window appears, enter how many frames do you want. The more frames you put, the bigger the document. Now all you have to do is change the times in the frames and then don't forget to save as Save Optimized as...

And there is your animation.

Another example.