Embodiments of this specification provide methods and apparatuses for processing images, devices, and storage media. A method includes: obtaining an image for processing; generating a first mask image corresponding to the image based on a machine-learning model and determining whether the image has a foreground object; in response to determining that the image has the foreground object, setting pixels corresponding to the foreground object to a first grayscale value range, and setting pixels corresponding to non-foreground objects in the first mask image to a second grayscale value range; determining an outline corresponding to the foreground object in the image according to a grayscale value range difference between the first grayscale value range of the foreground object and the second grayscale value range of the non-foreground objects in the first mask image; and sending, to a client device for display, the image with the determined outline for interaction by a user.