1. An image processing method comprising: calculating a similarity between a current image and a previous image; selecting a compression algorithm from a plurality of preset compression algorithms based upon the calculated similarity; and compressing the current image based upon the selected compression algorithm, wherein the selecting of the compression algorithm comprises: comparing the calculated similarity with a preset threshold value; providing preset compression algorithms organized by levels, each subsequent level having a higher loss factor; selecting a compression algorithm having a priority one level higher than that of a compression algorithm used upon compression of the previous image, from a plurality of compression algorithms each having a preset priority, when the calculated similarity is higher than the threshold value; and selecting a compression algorithm having a priority one level lower than that of a compression algorithm used upon compression of the previous image, from the plurality of compression algorithms each having the preset priority, when the calculated similarity is lower than or equal to the threshold value.