Removing: Basically you have to remove the postprocess views (including resetting the .stage pointers) and remove all bmap-buffers that were used.

When resizing, for each view that changes size: Remove the bmap, create a new one with the appropriate dimensions and update all your pointers. This has to be done within one frame, otherwise you have to prevent the post-process stages from rendering (basically everything that uses your bmap would break stuff as the pointer is no longer valid).