DOC run optipng before uploading website

Conflicts:
	doc/Makefile

doc/Makefile

@@ -12,7 +12,7 @@ PAPEROPT_a4     = -D latex_paper_size=a4
 PAPEROPT_letter = -D latex_paper_size=letter
 ALLSPHINXOPTS   = -d $(BUILDDIR)/doctrees $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) .
 
-.PHONY: help clean html dirhtml pickle json htmlhelp qthelp latex latexpdf changes linkcheck doctest
+.PHONY: help clean html dirhtml pickle json latex latexpdf changes linkcheck doctest optipng
 
 all: html-noplot
 
@@ -107,3 +107,9 @@ doctest:
 
 download-data:
 	python -c "from sklearn.datasets.lfw import check_fetch_lfw; check_fetch_lfw()"
+
+# Optimize PNG files. Needs OptiPNG. Change the -P argument to the number of
+# cores you have available, so -P 64 if you have a real computer ;)
+optipng:
+	find _build auto_examples */generated -name '*.png' -print0 \
+	  | xargs -0 -n 1 -P 4 optipng -o10

doc/README

@@ -21,13 +21,21 @@ To build the PDF manual, run
 Upload the generated doc to sourceforge
 ---------------------------------------
 
-First of, generate the html documentation::
+First off, generate HTML documentation::
 
     make html
 
 This should create a directory _build/html/stable with the documentation in
 html format.
 
+Next, make sure you have the PNG optimizer OptiPNG installed.
+The PNG files generated by Matplotlib tend to be ~20% too big, and they're
+costing us bandwidth. Then issue::
+
+    make optipng
+
+This may take some time. If you have a big machine at your disposal,
+check the ``Makefile``; it has a hint on how to speed up this target.
 
 Now can upload the generated HTML documentation using scp or some other SFTP
 clients.