Electronic device including preview images for background screen for flexible display and control method thereof

An electronic device comprising:

• a housing;
• a display having a display area including a first display area and a second display area, wherein the first display area is exposed regardless extension and reduction of the electronic device and the second display area is exposed from the housing and hidden by the housing according to respectively extension and reduction of the electronic device;
• and
• at least one processor operatively connected to the display,
• wherein the processor is configured to:
• select an image for a background screen based on a first user input,
• display at least one preview image corresponding to the image for setting the background screen, the at least one preview image including a first area of the image corresponding to the first display area and a second area of the image corresponding to the second display area, the first area and the second area being visually recognizable,
• specify the image as the background screen, based on a first second user input, and
• display a portion of the background screen corresponding to the first area of the image when the electronic device is reduced and display at least a portion of the background screen corresponding to the first and second area of the image when the electronic device is extended.