A video management system includes: an imaging device configured to generate a first image by capturing a surveillance area at a first resolution; and a video management server configured to store a second image by converting the first image, wherein the imaging device includes: a high-resolution image storage configured to store the first image; a processor configured to convert the first image into the second image having a second resolution that is lower than the first resolution; and to transmit the second image to the video management server, and the video management server includes: a low-resolution image storage configured to store the second image; and a processor configured to generate low-resolution image metadata and an index of the low-resolution image metadata by analyzing the second image.