1. A system for analyzing wound status, comprising: an image obtaining device configured to obtain a plurality of infrared (IR) images which are pictured from a wound of a user's body portion, wherein the plurality of IR images include a first IR image pictured at a first time and a second IR image pictured at a second time, the first IR image includes a first pattern image of vascular distribution of the user's body portion and the second IR image includes a second pattern image of vascular distribution of the user's body portion; and an image analyzing device, coupled to the image obtaining device, including: a wound detecting module configured to detect a first wound image region from the first IR image, and detects a second wound image region from the second IR image; an image calibrating module configured to respectively recognize a non-wound region from the first IR image and a non-wound region from the second IR image to obtain a first feature group and a second feature group, produce calibration information according to the first feature group and the second feature group, and utilize the calibration information for aligning the second IR image to the first IR image to produce a calibrated image; and a wound analyzing module configured to recognize a third wound image region from the calibrated image and compares the third wound image region and the first wound image region for finding out variations of the wound.