composite image; photomontage; photoshopped image
Internet slang for an image created by combining or manipulating parts of other images, often for humorous or deceptive purposes. コラ comes from コラージュ (collage).
See also: コラ
That composite image is really well made, isn't it?
A photoshopped image of a celebrity was spread on social media.
Abbreviation of コラージュ (collage) + 画像 (image). The term emerged in Japanese internet communities to describe manipulated images.