Use source keyword argument (instead of overriding get_attribute)
Use source keyword argument (instead of overriding get_attribute)

This allows the ImageRenditionField to be used on models that contain an
image field.

zerolab/wagtail,kaedroho/wagtail,iansprice/wagtail,mikedingjan/wagtail,nealtodd/wagtail,wagtail/wagtail,thenewguy/wagtail,thenewguy/wagtail,timorieber/wagtail,nimasmi/wagtail,mixxorz/wagtail,torchbox/wagtail,gasman/wagtail,thenewguy/wagtail,zerolab/wagtail,takeflight/wagtail,torchbox/wagtail,nimasmi/wagtail,rsalmaso/wagtail,Toshakins/wagtail,timorieber/wagtail,rsalmaso/wagtail,wagtail/wagtail,mikedingjan/wagtail,iansprice/wagtail,wagtail/wagtail,timorieber/wagtail,kaedroho/wagtail,nimasmi/wagtail,wagtail/wagtail,nealtodd/wagtail,FlipperPA/wagtail,kaedroho/wagtail,jnns/wagtail,iansprice/wagtail,Toshakins/wagtail,thenewguy/wagtail,gasman/wagtail,thenewguy/wagtail,takeflight/wagtail,takeflight/wagtail,gasman/wagtail,mixxorz/wagtail,Toshakins/wagtail,iansprice/wagtail,Toshakins/wagtail,nealtodd/wagtail,zerolab/wagtail,mixxorz/wagtail,timorieber/wagtail,zerolab/wagtail,jnns/wagtail,wagtail/wagtail,FlipperPA/wagtail,kaedroho/wagtail,torchbox/wagtail,mixxorz/wagtail,jnns/wagtail,kaedroho/wagtail,jnns/wagtail,mikedingjan/wagtail,torchbox/wagtail,gasman/wagtail,rsalmaso/wagtail,gasman/wagtail,FlipperPA/wagtail,FlipperPA/wagtail,zerolab/wagtail,rsalmaso/wagtail,nimasmi/wagtail,takeflight/wagtail,mixxorz/wagtail,rsalmaso/wagtail,nealtodd/wagtail,mikedingjan/wagtail