1. An image recording apparatus comprising: an image data storage unit which stores image data regarding an image recorded on a recording medium; a record head which records the image by ejecting recording droplets onto the recording medium; a head controller which controls ejection of the recording droplets from the record head based on the image data stored in the image data storage unit so that image dots are formed as the recording droplets are ejected onto the recording medium; an image data changing unit which changes the image data stored in the image data storage unit so that an amount of the ejected recording droplets is reduced; an edge detection unit which detects an edge of the image concerning the image data; a thin-line image portion judging unit which judges that a portion in the image which portion is not wider than a first predetermined length in a direction orthogonal to an extending direction of the edge detected by the edge detection unit is a thin-line image portion; and a thin-line blank region judging unit which judges that a blank region which neighbors an edge of the thin-line image portion and does not receive the recording droplets is a thin-line blank region when the blank region is not wider than a second predetermined length in a direction orthogonal to the extending direction of the edge of the thin-line image portion, wherein, the image data changing unit changes the image data such that an amount of reduction in the recording droplets ejected onto a region including a dot region where the image dots constituting at least the edge of the thin-line image portion are formed is large when the thin-line image portion neighbors the thin-line blank region, as compared to a case where the thin-line image portion does not neighbor the thin-line blank region.