1. A method for synthesizing an image with multi-view images, comprising: inputting a plurality of reference images, wherein each of the reference images is photographed correspondingly to a reference viewing-angle; determining an intended synthesized image corresponding to a viewpoint and an intended viewing-angle; segmenting the intended synthesized image to obtain a plurality of meshes and a plurality of vertices of the meshes; respectively constructing a viewing-angle between the viewpoint and each of the vertices; searching a plurality of neighbouring images corresponding to each of the vertices among the reference images according to the viewing-angle; determining a plurality of possible vertex depth values, wherein one of the possible vertex depth values for each one of the vertices is determined by the following two steps: projecting a position of each one of the vertices onto each of the neighbouring images at a projection position according to each one of the possible vertex depth values, wherein for each one of the vertices, each one of the possible vertex depth values has a corresponding set of image areas as respectively projected on the neighbouring images; and for each one of the vertices, analyzing an image correlation value of the neighbouring images at each set of image areas, wherein the one of the possible vertex depth values has the best image correlation value is a proper depth value for the one of the vertices; and performing image synthesizing to produce the intended synthesized image according to the points corresponding to the proper depth values of the vertices, wherein when at least one of the neighbouring images falls within an adjacent region of the vertex, the intended synthesized image is produced in a first mode; when none of the neighbouring images falls within the adjacent region of the vertex, the intended synthesized image is produced in a second mode.