A method of transferring information signals representing still images, video audio and/or other data comprises sending, the information signals to a recipient apparatus or "viewer" 10 from a server 2 via a network 12. Data indicative of whether or not further data is to be embedded in the information signals is also sent either with the signals or separately. The further data is embedded in the information signals at the viewer 10 in dependence upon the indicative data. The further data is perceptible in the information signals as to degrade them.