A sizes were created so that, for example, A4 is twice the area of A5, but the same shape. I use A4 for mounted prints, and A5 and A6 for cards. These images can be used on any of these formats.
A4 prints are offered in A3 or 16″x12″ mounts at £15 or framed at £25. They are printed on glossy photo paper using long life inks. Cards are also available with high quality photos mounted on them. Cards are blank inside to suit a wide variety of uses. A5 cards cost £3, and A6 cards cost £1.50
Some designs are available as printed cards. These are sold in small sets (e.g. 5 cards for £4)