diff --git a/doc/PSI.gif b/doc/PSI.gif
deleted file mode 100644
index ccbcda8..0000000
Binary files a/doc/PSI.gif and /dev/null differ
diff --git a/doc/PSI.png b/doc/PSI.png
new file mode 100644
index 0000000..ef9f572
Binary files /dev/null and b/doc/PSI.png differ