An electronic device, comprising: at least one processor, configured to be coupled to an image capture unit; and a non-transitory computer-readable medium storing computer-executable instructions to be executed by the at least one processor for performing an image capture method and storing a plurality of predetermined facial patterns corresponding to different types or different degrees of facial expressions, wherein the image capture method comprises: entering an automatic capture mode; periodically refreshing a preview image captured by the image capture unit; detecting a facial expression from a current preview image; determining whether the facial expression matches any one of the predetermined facial patterns; determining whether the matched one of the predetermined facial patterns matches a previous matched facial pattern only if the facial expression matches one of the stored predetermined facial patterns, otherwise refreshing the current preview image, the previous matched facial pattern being determined by matching a previous facial expression from a previous preview image to the predetermined facial patterns, and if the current matched facial pattern matches a previous matched facial pattern, refreshing the current preview image; capturing a target image according to the preview image only if the matched one of the predetermined facial patterns does not match the previous matched facial pattern, updating the previous matched facial patterns by adding the matched one of the predetermined facial patterns, and refreshing the current preview image. at least one processor, configured to be coupled to an image capture unit; and a non-transitory computer-readable medium storing computer-executable instructions to be executed by the at least one processor for performing an image capture method and storing a plurality of predetermined facial patterns corresponding to different types or different degrees of facial expressions, wherein the image capture method comprises: entering an automatic capture mode; periodically refreshing a preview image captured by the image capture unit; detecting a facial expression from a current preview image; determining whether the facial expression matches any one of the predetermined facial patterns; determining whether the matched one of the predetermined facial patterns matches a previous matched facial pattern only if the facial expression matches one of the stored predetermined facial patterns, otherwise refreshing the current preview image, the previous matched facial pattern being determined by matching a previous facial expression from a previous preview image to the predetermined facial patterns, and if the current matched facial pattern matches a previous matched facial pattern, refreshing the current preview image; capturing a target image according to the preview image only if the matched one of the predetermined facial patterns does not match the previous matched facial pattern, updating the previous matched facial patterns by adding the matched one of the predetermined facial patterns, and refreshing the current preview image. entering an automatic capture mode; periodically refreshing a preview image captured by the image capture unit; detecting a facial expression from a current preview image; determining whether the facial expression matches any one of the predetermined facial patterns; determining whether the matched one of the predetermined facial patterns matches a previous matched facial pattern only if the facial expression matches one of the stored predetermined facial patterns, otherwise refreshing the current preview image, the previous matched facial pattern being determined by matching a previous facial expression from a previous preview image to the predetermined facial patterns, and if the current matched facial pattern matches a previous matched facial pattern, refreshing the current preview image; capturing a target image according to the preview image only if the matched one of the predetermined facial patterns does not match the previous matched facial pattern, updating the previous matched facial patterns by adding the matched one of the predetermined facial patterns, and refreshing the current preview image.