Electronic device capable of adjusting images automatically and method thereof

The invention provides a method for adjusting an image, comprising the steps of: providing an electronic device which comprises an input unit used for receiving user input and a display unit, obtaining an image to be copied and displaying on the display unit; adjusting the image on the display unit according to the user input; obtaining partial image; adjusting the resolution ratio of the partialimage according to the resolution ratio of the display unit; and copying the image file formed after adjusting the resolution ratio of the partial image to a target storage position. At the same time,the invention also provides an electronic device for adjusting the image. The electronic device can reserve the part of the image needed by the user and adapts to the display device to achieve betterdisplay effect.