Graphical image processing with levels of user access

A method of generating an executable graphic file for an animation. Graphic data defines first characteristics of an animation, which are accessible via locked parameters at a first level of user access. The graphic data also contains references to unlocked parameters stored as metadata in a metafile. The metadata preferably includes, for each unlocked parameter, a value field, a range of possible values and a description, thus making it possible to construct a user interface to modify second animation characteristics without modifying the graphic data. The graphic data is combined with rendering instructions, to form an executable animation file. Preferably the executable file cannot execute after a predetermined date. Multiple instances of the animation may be created by re-use and modification of the original metafile.