The purpose of this study is to investigate the usage of colors in the image by analyzing the webtoon thumbnails used as the representative image like a logo. It is expected that there is the correlation between the genre of webtoon and the color of the thumbnail because of the properties of colors. Accordingly, it will be needed to consider it when the thumbnails of webtoons are designed and produced. To come up with an answer of this question, this study has focused on examining the correlation between the colors and the identity of webtoons by analyzing the colors used in the thumbnails of webtoons, The result of this study is as follow: firstly, The dominant colors of the thumbnails of romance comics are orange, red, and yellow. secondly, Black, grey, orange and red are classified as the dominant color used in the thumbnails of thriller webtoons. Lastly, the dominant colors in the thumbnails of fantasy webtoons are orange, purple, red, yellow and navy. Judging by the above-mentioned results, it is expected that this study has drawn up the guidelines for designing and producing the thumbnails of webtoons.