A cloud streaming service system, an image cloud streaming service method using an application code, and a device therefor are disclosed. A still-image-based cloud streaming service can be performed by receiving a first code corresponding to an application result screen image from a web application server, generating a capture image by using image region attribute information included in the first code, still-image-encoded capture image and a second code generated so as to include animation information by converting the first code, such that the user terminal can generate the application result screen image. A cloud streaming server does not have to perform unnecessary rendering and does not perform animation processing, thereby enabling the number of web containers operable in the server to increase.