diff --git a/docs/3_Howto_guides_examples/Define_pop_Fig1.png b/docs/3_Howto_guides_examples/Define_pop_Fig1.png
new file mode 100644
index 0000000..3d91987
Binary files /dev/null and b/docs/3_Howto_guides_examples/Define_pop_Fig1.png differ
diff --git a/docs/3_Howto_guides_examples/Define_pop_Fig2.png b/docs/3_Howto_guides_examples/Define_pop_Fig2.png
new file mode 100644
index 0000000..58b4a69
Binary files /dev/null and b/docs/3_Howto_guides_examples/Define_pop_Fig2.png differ