Yes, it can be very disappointing as camera zoom function should be common in every phone with camera especially smartphones. Contact Samsung and let them know that you want zoom integrated in the Galaxy Attain's camera app so they can include it in future software updates.
The Samsung Galaxy Attain 4G camera app does not have zoom function. What you can do instead after taking a picture is to touch the Image Viewer to view the picture and touch the zoom icons to zoom incrementally, or double-tap on the picture to zoom all the way in or out.