What are the specifications, sizes and styles of photos? Theme? Concept, type?

One inch 2.5 x 3.6 cm 5x8 inches

Two inches 3.4 x 5.2 cm 5x9 inches

Three inches 5.5 x 8.4 cm 5x 10 inch

Five inches 3.5 x 5 5x 12 inch

Six inches 4 x 6 x 9 inches

7 inch 5 x 7 6x 10 inch

Eight inches 6 x 8 6x 12 inches

10 inch 8 x 10 6x 14 inch

12 inch10 x128.5x12 inch.

Fourteen inches10x14x10x14.5 inches.

Sixteen inches12x16x12x17 inches.

Eighteen inches12x1812x17.5 inches.

/kloc-within 0/8 inch, the number of inches shall prevail; over 20 inches, the number of centimeters shall prevail. Remarks: 1 inch = 2.54cm

20 inches 40 x 50 cm

Standard 24 inches 50 x 60 cm

24 inches 44 x 60 cm

24-inch hanging photo 42 x 60 cm

30 inches 60 x 75 cm

32 inches 60 x 80 cm

36 inches 60 x 90 cm

40 inches 70 x 100 cm

48 inches 90 x120cm

58 inches100x115cm

Sixty-eight inches 1 12 x 170 cm

As for the idea without boundaries, it is a kind of style.