title: GDAL function to split large image into specific chunks
body: <p>I would like to use GDAL if possible to split an image up to 3Gb into 100mb TIFs so that I can do processing on these smaller chunks.  After the processing I would like to reconstruct these images(which will look different) back into their original positions to create one large TIF again.  It seems like I can use ImageMagick to do this but I would like to stick with GDAL if possible.</p>
  
  <p>So, what functions would I use in GDAL to split and then reconstruct chunks? retile.py? polygonize.py?</p>