http proxy - images not loading - cyclic redirect

[milahu]

reproduce:
in firefox
set "proxy url" to http://server/ = remove the s from https

results:
images are not loading any more
the page keeps loading and loading, but images never show

when i click "view image", i see a long-long-long url
with the original url encoded over and over again, about 10 times
but isolated from the html context, the image shows up after a while

the problem also occurs in a new/empty firefox profile
only with the bandwidth-hero addon installed

side effect:
the "images processed" counter keeps growing and growing