The invention provides an electronic device, and an image processing method and system of an application. A first cache mapping table is established for key values according to resource sizes, partial bytes and postfix names of downloaded pictures, and the pictures are cached locally according to the first cache mapping table. When the pictures need to be downloaded subsequently, the matched pictures can be searched locally according to the postfix names, resource sizes and partial bytes of to-be-downloaded pictures; if there are matched pictures, the pictures are directly obtained; and if there is no matched picture, the pictures are downloaded from a control end. The pictures are prevented from being downloaded repeatedly, and the picture obtaining efficiency is high; matching is carried out for the key values according to the postfix names, resource sizes and partial bytes of the pictures, and the matching accuracy is improved; and the problem that in the prior art, the processing efficiency is reduced due to the fact that the matching is carried out for the key values only according to the picture names, the matching result is inaccurate, and the pictures need to be downloaded repeatedly is prevented.