Update doc/images/sample_box_red.png, doc/images/sample_box_green.png,...
Update doc/images/sample_box_red.png, doc/images/sample_box_green.png, doc/images/sample_box_blue.png files
Update doc/images/sample_box_red.png, doc/images/sample_box_green.png, doc/images/sample_box_blue.png files
merged
mentioned in commit 4c5a1c1d