black background color

[chanyeong]

Why is it the image display with black background color??
My uploaded image is without the black color border..

here is the image: url

[jplehmann]

Probably related to transparency and changing image formats. See my issue #415.

[sbor23]

Little late to the party, but maybe it helps a future reader.
If you use the convert engine, you want to add THUMBNAIL_FLATTEN=True to your settings.
Unfortunately this setting is not documented.