Here’s what consumers have asked with answers from Photobox staff and previous consumers.
Same here with Grandparents Christmas present- of all years to have to hand over an IOU! Will use a more reputable company on future.
You may choose 5cm x 5cm (Medium) or 7cm x 7cm (Large)
They weren't especially strong magnets. I think more for decoration vs function, they might hold a light piece of paper.
Not sure I only used when I had a 4. I thought it was good quality though.