A server (600), a client device (602) and methods therein, for handling cached content resources. When the client device (602) sends a download request (6:3) in a downloading session, the server (600) identifies (6:4) at least one content resource deemed to be potentially needed later in the downloading session. The server (600) then sends a cache map to the client device (602) in a response to the download request. The cache map comprises a pre-fetch indication indicating that the identified at least one content resource should be pre-fetched by the client device (602) from a cache (604) containing the identified at least one content resource. Thereby, the client device is able to pre-fetch (6:8) the content resources before the performance of communication may become reduced so that communication with the cache (604) is difficult or even impossible, e.g. due to deteriorated radio conditions or congestion in the communication network.