How can ‘wrap’ an image to a div? [closed]

so essentially I have an image that ‘hugs’ the bottom of the div (image background). i need the gray portion under the blue – red image to be white. how would I go on about doing that? the red-blue image is a psuedo element FYI but I can change it to an element if need be. I tried hacky ways but it gets ruined when U test with different amounts of text and height of the div. tried to just go in photoshop and just paint it white but it got too messy