tiff2pict (filename) Given a string that is the name of a file, reads that file in TIF form, presumably a b/w scanned file, and returns a picture structure: width, height, x-y coordinate of the lower left corner (0,0 for a full page), and the collection of rows.
pict2tiff (p, "filename.tif") writes back out to the file system the picture p as a tif file with name filename.tif.
pict2bit (p) converts a picture structure p into a bitmap b, suitable for display using the Common Windows package. A bitmap is an official data structure used by the Common Windows package in Common Lisp, If WIN is a Common Windows window descriptor for a visible window, and p is a picture then (bitblt (pict2bit p) 0 0 WIN 0 0) transfers the image of the picture p starting at its lower left, into the window WIN at its lower left.
bit2pict (b) takes a bitmap b, as might be produced by interactive editing, and returns a picture structure. Since the Common Windows programs use the bitmap structure, it is plausible to (for example) write character editing or similar manipulation programs using bitmaps, and then translate the results to a pict form.