How to decode the pixels in a JPG in App Engine (using pure python)?

Question

Using python App Engine I need to convert a JPG image that is one 9 MB file (of Pakistan's floods) into many PNG tiles.

For the PNG part, I already know how to use PyPNG, which is great. Note: PIL cant be used with App Engine.

So how do I decode the JPG into pixel data?

Answer 1

Using Image class and crop and execute_transforms to encode as png?

Note: You should provide relevant part of your code

Answer 2

You can use the efforts here to get a pure python JPEG Parser. Why the absolute need to use App Engine ? If you want more flexible library usage try EC2.