The best Python/Django architecture for image heavy web application
If you use django-photologue, you can define a thumbnail size and specify that the thumbnail should not be generated at upload time - instead, it gets generated the first time the thumbnail is requested for display.
If you have lots of different sized thumbnails for a photo, this trick can help a user upload their photos faster.
Source: I maintain django-photologue.
I am building a web application that allows users to upload images to their accounts - similar to flickr and 500px. 
I want to know the best setup for such an application. I'm using Python 3.4 and Django 1.9
I'm currently thinking about the following:

Heroku
AWS S3
Postgres

I'm struggling to find a suitable image processing library. I've looked at ImageKit and Photologue. But I find Photologue to be a little bit heavy for what I want to do.
I'm basically looking for a way to allow users to upload images of a certain size without locking up the Heroku dynos. Any suggestions? 
Thanks