diff --git a/modules/aruco/tutorials/aruco_board_detection/aruco_board_detection.markdown b/modules/aruco/tutorials/aruco_board_detection/aruco_board_detection.markdown
index 95d3a3dc3..6ce8603ec 100644
--- a/modules/aruco/tutorials/aruco_board_detection/aruco_board_detection.markdown
+++ b/modules/aruco/tutorials/aruco_board_detection/aruco_board_detection.markdown
@@ -156,7 +156,7 @@ In this case the margin is 10.
 
 The output image will be something like this:
 
-![](images/board.jpg)
+![](images/board.png)
 
 A full working example of board creation is included in the `create_board.cpp` inside the `modules/aruco/samples/`.
 
diff --git a/modules/aruco/tutorials/aruco_board_detection/images/board.jpg b/modules/aruco/tutorials/aruco_board_detection/images/board.png
similarity index 100%
rename from modules/aruco/tutorials/aruco_board_detection/images/board.jpg
rename to modules/aruco/tutorials/aruco_board_detection/images/board.png
diff --git a/modules/aruco/tutorials/charuco_detection/charuco_detection.markdown b/modules/aruco/tutorials/charuco_detection/charuco_detection.markdown
index 3ed729db9..ddcd5e91b 100644
--- a/modules/aruco/tutorials/charuco_detection/charuco_detection.markdown
+++ b/modules/aruco/tutorials/charuco_detection/charuco_detection.markdown
@@ -88,7 +88,7 @@ In this case the margin is 10.
 
 The output image will be something like this:
 
-![](images/charucoboard.jpg)
+![](images/charucoboard.png)
 
 A full working example is included in the `create_board_charuco.cpp` inside the `modules/aruco/samples/`.
 
diff --git a/modules/aruco/tutorials/charuco_detection/images/charucoboard.jpg b/modules/aruco/tutorials/charuco_detection/images/charucoboard.png
similarity index 100%
rename from modules/aruco/tutorials/charuco_detection/images/charucoboard.jpg
rename to modules/aruco/tutorials/charuco_detection/images/charucoboard.png
diff --git a/modules/bioinspired/tutorials/retina_illusion/images/checkershadow_illusion4med_proof.jpg b/modules/bioinspired/tutorials/retina_illusion/images/checkershadow_illusion4med_proof.png
similarity index 100%
rename from modules/bioinspired/tutorials/retina_illusion/images/checkershadow_illusion4med_proof.jpg
rename to modules/bioinspired/tutorials/retina_illusion/images/checkershadow_illusion4med_proof.png
diff --git a/modules/bioinspired/tutorials/retina_illusion/retina_illusion.markdown b/modules/bioinspired/tutorials/retina_illusion/retina_illusion.markdown
index 847321e54..024879e02 100644
--- a/modules/bioinspired/tutorials/retina_illusion/retina_illusion.markdown
+++ b/modules/bioinspired/tutorials/retina_illusion/retina_illusion.markdown
@@ -30,7 +30,7 @@ values of the two squares with the picker tool.
 
 In this image I've cropped a little piece of the A and B squares and I've put them side-by-side.
 It should be quite evident they have the same luminance.
-![Adelson checkerboard proof](images/checkershadow_illusion4med_proof.jpg)
+![Adelson checkerboard proof](images/checkershadow_illusion4med_proof.png)
 
 It's worth to know that this illusion works because the checkerboard image, as you may see it
 on your laptop, casts on your retina with dimensions that cause the retina local adaptation to take
@@ -184,4 +184,4 @@ opportunity of writing this tutorial, and for reviewing it.
 
 **Edward Adelson** - for allowing me to freely use his checkerboard image.
 
-**Antonio Cuni**  - for reviewing this tutorial and for writing the Python code.
\ No newline at end of file
+**Antonio Cuni**  - for reviewing this tutorial and for writing the Python code.