I have a year old photo of my two boys that was done at a Sears Photo Studio. I have it hanging in the hallway with several other photos. For some reason, the photo has adhered to the glass front of the frame in some places, like glue. The other photos around it are fine and have not done this. The picture looks strange with half stuck to the glass and half not. I'm afraid if I try to peel it the pigmet will come off and the photo will be ruined. Is there any way to do this safely? I presume using some matting will prevent it in the future, is there another way?