Electronic device for processing image and image processing method thereof

An electronic device comprising:

• a memory;
• and
• a processor electrically connected with the memory,
• wherein the memory stores instructions that, when executed, cause the processor to control the electronic device to:
• obtain information about a maximum brightness value of image content based on metadata of the image content;
• determine whether the maximum brightness value satisfies a first condition associated with reliability of the maximum brightness value;
• determine a normalizing factor according to a first operation based on the maximum brightness value being determined to satisfy the first condition or according to a second operation different from the first operation based on the maximum brightness value being determined to not satisfy the first condition;
• perform tone mapping on at least one frame corresponding to a thumbnail image of the image content based on the determined normalizing factor;
• and
• control to output the thumbnail image based on the at least one frame on which the tone mapping is performed, on a display device.