README update

README.rst

@@ -14,7 +14,7 @@ Installation
 This module requires `psd-tools`_, packbits_ and distribute_.
 
 .. _Pymaging: https://github.com/ojii/pymaging
-.. _psd-tools: http://pypi.python.org/pypi/psd-tools/
+.. _psd-tools: https://github.com/kmike/psd-tools
 .. _packbits: http://pypi.python.org/pypi/packbits/
 .. _distribute: http://pypi.python.org/pypi/distribute
 
@@ -29,3 +29,9 @@ Development happens at github and bitbucket:
 The main issue tracker is at github: https://github.com/kmike/pymaging-psd/issues
 
 Feel free to submit ideas, bugs, pull requests (git or hg) or regular patches.
+
+Please note that pymaging-psd is a simple wrapper for `psd-tools`_ and
+does almost nothing: it just registers the image format and provides
+a distribute entry point. If something doesn't work, this is likely a bug in
+`psd-tools`_ (or maybe in Pymaging_) and should be reported to the
+appropriate bug tracker.