1. A method for determining a type of an area included in an image, the method comprising: generating a binary image by binarizing the image; calculating a binary pixel ratio that is a ratio of a binary pixel quantity that is a quantity of dotted pixels included in a specific area of the binary image to a total quantity of pixels included in the specific area of the binary image; generating a thin-line image by performing a line-thinning process on the specific area; calculating a thin-line pixel ratio that is a ratio of the quantity of dotted pixels included in the thin-line image to the binary pixel quantity; and determining that the specific area is a map area or a photograph area based on the calculated binary pixel ratio and the calculated thin-line pixel ratio.