Loading Background Images for rendering or as guiding helpers in modeling.
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A) Environment bkgnd image.
Is used in rendering.
Image is always 'static'.
View size is used when image is drawn(image stretched).
Image is used by all views.









B) Viewport bkgnd image.
Isn't used in rendering.
Image is aligned to view(rotated,moved,zoomed ).
Image size is used when drawn.
You can have different images for each view or the same for all.

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