photoshop can't open some types of bitmip images.
ie. if u saved a image in bitmip format using eagraph then photoshop can't open it..
but if u extract the bitmip images using fshtool u can view it....
i dunno why, but yeh thats wat happens to me,
i normall save all my images after i work with them in psd format. so that the layers are intact incase i wanna remove or add anything