1. A method for processing digital image data utilizing a vertically-oriented Effect graph, the digital image data being processed from a bottom of the Effect graph to a top of the Effect graph, the method comprising: receiving the vertically-oriented Effect graph, wherein the Effect graph includes a first Effect object, a second Effect object, and a third Effect object, wherein an output of the first Effect object and the output of the second Effect object provide an input to the third Effect object, and wherein the Effect graph is utilized to process digital image data; receiving digital image data to be processed utilizing the Effect graph; performing a first processing pass and a second processing pass of the Effect graph from the bottom to the top thereof along a first of two potential divergent paths, wherein the first and second processing passes include the first and second Effect objects; caching at least a portion of the digital image data in an image buffer associated with the output of the first and second Effect objects during processing; determining that the first Effect object has been modified from the first processing pass to the second processing pass, wherein the first Effect object has been modified when a parameter value of the first Effect object has been adjusted; setting a dirty flag of the first Effect object indicating that the first Effect object has been modified from the first processing pass to the second processing pass; in response to the dirty flag associated with the first Effect object, disposing of the cached data in the image buffer corresponding to the output of the first Effect object such that the first Effect object is re-rendered during a next processing pass; and performing a third processing pass of the Effect graph in accordance with the first of the two potential divergent paths, wherein the third processing pass re-renders the first Effect object based on the dirty flag associated with the first Effect object, wherein the digital image data cached in the image buffers associated with the output of the second Effect object is retrieved and used in the second and third processing passes as the second Effect object is not re-rendered based on that the second Effect object has not been modified since the first processing pass.