[Zope] Saving PIL Images on zope

I am using Plone3 and zope 2.10, I need to save PIL images generated through MatplotLib Graphs using External Methods to my zope site I have used addImage(self,'%s' % img_id, title = '%s' % img_id, file=image_data.getvalue() ) which adds image as a content type and also on the current context Is there any other way to save images on my local zope site?