$ pip install Flask-Imagine

from flask import Flask
from flask.ext.imagine import Imagine

app = Flask(__name__)

app.config['IMAGINE_ADAPTER'] = {
    'name': 'fs',
    'source_folder': 'images',  #  Relative to 'static' folder
    'cache_folder': 'cache'     #  Not required. Default: 'cache'
}

app.config['IMAGINE_FILTER_SETS'] = {
    'filter_set_name': {
        'cache': True,
        'filters': {
            #  Filters initialization parameters
        }
    }
}

# ... Another configuration options

# Init extension
imagine = Imagine(app)
#  or 
imagine = Imagine()
imagine.init_app(app)