getImage method inside ATFile

can somebody explain me why there is a getImage method on the File 
content type?

(Pdb) item
<ATFile at /Plone/my_file.pdf>
(Pdb) item.image
*** AttributeError: image
(Pdb) item.getImage
<bound method ATBlob.getImage of <ATFile at /Plone/my_file.pdf>>
(Pdb) item.getImage()
<plone.app.blob.field.BlobWrapper object at 0x7f9ae0e1c1b8>

is this a bug on plone.app.blob? I don't see were do we get it:

https://github.com/plone/plone.app.blob/blob/master/src/plone/app/blob/field.py

best regards
-- 
Héctor Velarde

------------------------------------------------------------------------------
Get 100% visibility into Java/.NET code with AppDynamics Lite!
It's a free troubleshooting tool designed for production.
Get down to code-level detail for bottlenecks, with <2% overhead. 
Download for free and get started troubleshooting in minutes. 
http://pubads.g.doubleclick.net/gampad/clk?id=48897031&iu=/4140/ostg.clktrk

_______________________________________________
Plone-developers mailing list
Plone-developers-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
https://lists.sourceforge.net/lists/listinfo/plone-developers