A projection device, comprising: an information input unit connectable to an electronic device; a storage unit, comprising a first storage block and at least one second storage block, wherein the first storage block is configured to store a preset startup image file; a scaling unit, connected to the information input unit and the storage unit, and configured to receive an identification request from the electronic device by the information input unit and return a projection device information to the electronic device according to the identification request, wherein the projection device information includes a size of the second storage block, and wherein the electronic device is configured to receive a selection instruction or an image capturing instruction to obtain a personalized startup image, adjust a resolution of the personalized startup image according to the projection device information, compress the adjusted personalized startup image to generate a personalized startup image file, and send the compressed personalized startup image file, and wherein the information input unit is configured to receive the compressed personalized startup image file; wherein the scaling unit is configured to generate a projected image signal according to the compressed personalized startup image file, and the scaling unit is configured to store the compressed personalized startup image file to the at least one second storage block; and wherein the projection device further comprises: an image processing unit, connected to the scaling unit, and configured to generate a projection control signal according to the projected image signal; and a projection unit, connected to the image processing unit, and configured to generate an image beam according to the projection control signal and project the image beam on a projection surface to form a startup image screen. an information input unit connectable to an electronic device; a storage unit, comprising a first storage block and at least one second storage block, wherein the first storage block is configured to store a preset startup image file; a scaling unit, connected to the information input unit and the storage unit, and configured to receive an identification request from the electronic device by the information input unit and return a projection device information to the electronic device according to the identification request, wherein the projection device information includes a size of the second storage block, and wherein the electronic device is configured to receive a selection instruction or an image capturing instruction to obtain a personalized startup image, adjust a resolution of the personalized startup image according to the projection device information, compress the adjusted personalized startup image to generate a personalized startup image file, and send the compressed personalized startup image file, and wherein the information input unit is configured to receive the compressed personalized startup image file; wherein the scaling unit is configured to generate a projected image signal according to the compressed personalized startup image file, and the scaling unit is configured to store the compressed personalized startup image file to the at least one second storage block; and wherein the projection device further comprises: an image processing unit, connected to the scaling unit, and configured to generate a projection control signal according to the projected image signal; and a projection unit, connected to the image processing unit, and configured to generate an image beam according to the projection control signal and project the image beam on a projection surface to form a startup image screen. an image processing unit, connected to the scaling unit, and configured to generate a projection control signal according to the projected image signal; and a projection unit, connected to the image processing unit, and configured to generate an image beam according to the projection control signal and project the image beam on a projection surface to form a startup image screen.