Citing an altered image

An image has been altered for educational purpose (eg. presentation), so Fair Use applies. How should the "new" image be cited?

Courtesy to Julie Stielstra, Knowledge Resource Library, Central DuPage Hospital, Winfield, IL, here is how the "new" image was cited:

iStockphoto [Internet]. Calgary, Alberta, Canada: Getty Images c2009 -
[retrieved 2009 September 1]. Original available from:
http://www.istockphoto.com/stock-photo-6388736-human-lung.php. Edited
by: Cook S, 2009.

One publisher, Rebecca Lawrence from Product Manager, F1000 Pharma, also made comments on this:

As a publisher, we always look at how much has changed from the original
image. If there was very significant change to the point that you could
claim that you created the image yourself then you probably are ok for
fair use. If it is a more minor change based on an obvious copy of the
original image (which it sounds like this will be) then you should get
permission not just from the author (which is out of politeness rather
than necessity), but if the image is copyright-protected, then also
written permission from the publisher, which in some cases can incur a
small fee. The citation would normally read:

For a copied image: 'Reproduced with kind permission from [the normal
reference citation of the document from which the original image came]'

For an altered image 'Based on, with kind permission from [the normal
reference citation of the document from which the original image came]'

Or similar wording to that effect. As there is such a standard
structure to the lungs and there are hundreds of drawings of them which
are all going to look similar by default, she might be better to get the
whole image redrawn in-house so that as long as it looks different to
the original image then she should be completely free of copyright
issues.