A method of managing a network bandwidth by controlling of an image compression rate and controlling of a frame generation, and an image transmission system using the same are provided. The method includes approving generation of an intra-frame (I-frame) for one among a plurality of image compression hardware (H/W) units, storing compressed image data compressed by the plurality of image compression H/W units in a plurality of buffers corresponding to the plurality of image compression H/W units, controlling a data storage level of the plurality of buffers, and encapsulating the compressed image data stored in each of the plurality of buffers into a network packet and transmitting the encapsulated image data to the outside through an external network.