i can resize it but it will not go back to the orginal size.i have some fine detail i am tryimg to do.how can i just enlarge and then go back to orginal size?
What is the resolution of your composition? PS Touch compositions have a max resolution of 1600x1600 pixels. This is (I imagine) to balance performance with features.
In PS touch , the image size doesn't get change it remains the same all the time only the zoom level chages , hence note the zoom level at the begining of the project and get back to it once you have zoomed in or out.
My first inclination based on your description (like others) would be to zoom way in on the image to be able to do whatever detailed work you wanted, after which you could zoom back out once you were completed. You can zoom in or out by pinching or expanding with two fingers on the screen. If you've tried this and are still having difficulties maybe it would be possible to post a screen shot of the image you are doing the detailed work on to better understand?