just checked this with Cyberfox (x64 fork of Firefox + adblocker & privacy badger running on a fairly new Core i5 laptop with Win 7 )) – got the same warning as yourself.
Tried an experiment to see what happens with the pictures if I try to download a picture using http rather than https – https works but http redirected to what I think is the home page (not the picture I expected).
Repeated this with a Linux box (original model B RPI (the one which doesn’t crash when exposed to strong light) with Raspbian)
[IMG]https://www.partyvibe.org/forums/attachment.php?attachmentid=154558&d=1448461704[/IMG]
on inspection the two jpgs obtained using wget and https are indeed pictures; when you use http the effect of the 301 redirect is more clearly shown – it is downloading something via https but the file size is completely different.
I then downloaded the 3 files to the Windows PC with WINSCP and tried to view them as pictures. The first two worked; the third smaller one did not and said the file is corrupt.
This is because it isn’t a jpg at all but a bunch of HTML code from the main page – I suspect therefore the 301 redirect is pointed to the wrong place or a generic destination to save DR B having to do hundreds of them individually. I wouldn’t class this as a security flaw as the result is still delivered via https but its not the expected content; which may well be what triggers a false alarm.
