An image-processing device comprising: an identifying unit configured to identify a first region and a second region (85ci, 85co) in a target image represented by target image data, the first region representing an encircling line for identifying a specific sub-region in the target image, the first region including a plurality of pixels, the second region being different from the first region, the second region including: an inside region that is surrounded by the first region; and an outside region that is outside the first region, the inside region having a plurality of internal pixels, the outside region having a plurality of external pixels; and a changing unit configured to change a color value of each of the plurality of pixels using a color value of one or more of the plurality of internal pixels and a color value of one or more of the plurality of external pixels; wherein the changing unit is configured to change a color value of a target pixel (Pt) included in the plurality of pixels using a color value of a first internal pixel included in the plurality of internal pixels and a color value of a first external pixel included in the plurality of external pixels; wherein the changing unit is configured to select a first internal reference pixel (P2s) and a first external reference pixel (P1s); wherein the changing unit is further configured to select the first internal pixel corresponding to the first internal reference pixel (P2s) and the first external pixel corresponding to the first external reference pixel (P1s); and change the color value of the target pixel using the equation as follows: Pti = D 2 s × P 1 i + D 1 s × P 2 i / D 1 s + D 2 s where D2s is a first distance between the target pixel (Pt) and the first internal reference pixel (P2s), D1s is a second distance between the target pixel (Pt) and the first external reference pixel (P1s), Pti is the color value of the target pixel (Pt), P2i is the average color value (P2ia) of non-encircling line pixels within calculation ranges centered on the first internal pixel, or color value (P2i) of the first internal pixel, and P1iis the average color value (P1ia) r of non-encircling line pixels within calculation ranges centered on the first external pixel, or color value (P1i) of the first external pixel. an identifying unit configured to identify a first region and a second region (85ci, 85co) in a target image represented by target image data, the first region representing an encircling line for identifying a specific sub-region in the target image, the first region including a plurality of pixels, the second region being different from the first region, the second region including: an inside region that is surrounded by the first region; and an outside region that is outside the first region, the inside region having a plurality of internal pixels, the outside region having a plurality of external pixels; and a changing unit configured to change a color value of each of the plurality of pixels using a color value of one or more of the plurality of internal pixels and a color value of one or more of the plurality of external pixels; wherein the changing unit is configured to change a color value of a target pixel (Pt) included in the plurality of pixels using a color value of a first internal pixel included in the plurality of internal pixels and a color value of a first external pixel included in the plurality of external pixels; wherein the changing unit is configured to select a first internal reference pixel (P2s) and a first external reference pixel (P1s); wherein the changing unit is further configured to select the first internal pixel corresponding to the first internal reference pixel (P2s) and the first external pixel corresponding to the first external reference pixel (P1s); and change the color value of the target pixel using the equation as follows: Pti = D 2 s × P 1 i + D 1 s × P 2 i / D 1 s + D 2 s where D2s is a first distance between the target pixel (Pt) and the first internal reference pixel (P2s), D1s is a second distance between the target pixel (Pt) and the first external reference pixel (P1s), Pti is the color value of the target pixel (Pt), P2i is the average color value (P2ia) of non-encircling line pixels within calculation ranges centered on the first internal pixel, or color value (P2i) of the first internal pixel, and P1iis the average color value (P1ia) r of non-encircling line pixels within calculation ranges centered on the first external pixel, or color value (P1i) of the first external pixel. where D2s is a first distance between the target pixel (Pt) and the first internal reference pixel (P2s), D1s is a second distance between the target pixel (Pt) and the first external reference pixel (P1s), Pti is the color value of the target pixel (Pt), P2i is the average color value (P2ia) of non-encircling line pixels within calculation ranges centered on the first internal pixel, or color value (P2i) of the first internal pixel, and P1iis the average color value (P1ia) r of non-encircling line pixels within calculation ranges centered on the first external pixel, or color value (P1i) of the first external pixel.