Photoshop provides facility to create animation or gif file using imageready. Here we are going to create twinkling stars background.
1. Open new document and fill black color in it using paint bucket tool.
2. select star brush if not available in photoshop then you can download it.
3. Take new layer and Using brush draw stars on screen.(Make sure your foreground color is white.)
4. go to imageready by clicking jump to imageready symbol in tools or press ctrl + shift + M.
5.In imageready there is animation pallet on left, below tools. if it is not visible then go to window->animation.
first frame is already present their. now take second frame in animation pallet.
6. take move tool from tools.
Move star layer to little upper right corner.
7. Then in animation pallet for each frame select frame delay time.
Then play or stop animation from animation pallet.
8. save animation and to save it as gif go to file->save optimized as or press alt + ctrl +shift +s. give name to file and save it. then to view gif file open it in any browser.