refactor tutorial for images
Tutorial for Image and ImageDef
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-Insert a raster image into a DXF document, the raster image is NOT embedded in
-the DXF file:
+This example shows how to use a raster image in a DXF document.
+Each IMAGE entity requires an associated IMAGEDEF entity in the objects
+section, which stores the filename of the linked image and the size in pixels.
+Multiple IMAGE entities can share the same IMAGEDEF entity.
+
+.. important::
+
+ The raster image is NOT embedded in the DXF file!
.. code-block:: Python
