Let's not jump the gun here. First of all, the OP indicates he/she is from Malta, so US copyright law does not apply. Maltese law may be similar, it may not be... HOWEVER, even under US law, I don't think the situation is quite so clear cut. There are situations where the photographer does NOT automatically own the copyright to an image; such as certain work for hire arrangements. In this case, I suspect that since the members of the group knew that it was not their camera, and since they had been requested to take a picture, it would not be reasonable to expect that in that setting, under those circumstances, just because you pushed the button, you owned the rights to the image.