Interleaving is an option for Image and related functions that specifies whether data corresponding to different channels in an object such as an image should be interleaved.
With the typical default setting Interleaving->True, objects are represented by an array of lists, where each list gives the value of each channel for each array element.
With Interleaving->False, objects are represented by a list of arrays, where each array gives all the values for a particular channel.