How can I make the images so that appengine doesn't transparent to black when resized?

Question

How can I make the images so that appengine doesn't transparent to black when resized?

I am on google appengine and am trying to resize images. I AM:

from google.appengine.api import images
image = images.resize(contents, w, h)

And for some images, I get a nice transparent size, while others get a black background.

How do I preserve transparency for all images?

Original: http://www.stdicon.com/g-flat/application/pgp-encrypted
Black: http://www.stdicon.com/g-flat/application/pgp-encrypted?size=64
Original: http://www.stdicon.com/gartoon/application/rtf
Black: http://www.stdicon.com/gartoon/application/rtf?size=64
Original: http://www.stdicon.com/nuvola/application/x-debian-package
Transparent: http://www.stdicon.com/nuvola/application/x-debian-package?size=64

+2

python google-app-engine resize python-imaging-library

Paul Tarjan 25 Sep '09 at 10:18

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3 answers

Nathan Ross Powell · Answer 1 · 2009-09-25T11:35:22+0000

An article on this issue: http://doesnotvalidate.com/2009/resizing-transparent-images-with-django-pil/ Google code patch: http://code.google.com/p/sorl-thumbnail/issues/ detail? id = 56

Nick johnson · Answer 2 · 2009-09-26T10:44:11+0000

Is it on the app server or in production? There's a known bug in the app server that becomes transparent to black when linking, but it should work fine.

Natim · Answer 3 · 2009-10-09T01:04:50+0000

With PIL, you need to convert your image to RGBA like this:

im = im.convert("RGBA")

If you want a more efficient implementation, you can read the sorl-thumbnail sketch code. This makes good use of PIL.

How can I make the images so that appengine doesn't transparent to black when resized?

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