There's a difference between clicking on the 'image' part of each photo and clicking on the frame SURROUNDING the photo itself. If you have more than one photo selected in the filmstrip for example and click on the photo part of one image, it becomes the 'most selected' image. If you have more than one photo selected and click on the frame of one of the images, it becomes the ONLY selected image. Try it and you'll see.
If you're in the Develop module and you have your images selected (and the current edit as the most selected), you can click on the 'Synch...' button to apply changes to all of them. If you want to copy the settings to only one photo, what you can do is (in the Develop module) click on the photo in the filmstrip that has the edits you want, then click on the photo to which you want to apply the changes and in the place of the 'Synch...' button you'll have a 'Previous' button. Lightroom will apply the develop settings of the previously selected image to the current image.
Mike.
