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Quru Image Server - dynamic imaging for web and print

QIS is a high performance web server for creating and delivering dynamic images. It is ideal for use in conjunction with your existing web site, for applications such as image galleries and product catalogues. Some of the application features are listed below, but for more information you can also read the application introduction and overview.

Quru has been using QIS in production since 2012, and the majority of source code is made available here under the Affero GPL license.

Please note that at present, one of the required runtime packages - qismagick - is not open source, and must be requested from Quru Ltd. This is due to some licencing restrictions which we are working on resolving. To request a copy, please send an email to

Quru also offers commercial support for the image server.

An example - HTML5 responsive images

With QIS it is a breeze to serve HTML5 responsive images without having to manually resize or store multiple copies of the same image.

First we upload a single high resolution image africa_dxm.png.
With different URLs we can then request scaled and cropped versions of the original:

Earth small Earth smaller Earth tiny crop

and with a snippet of HTML we can ask the web browser to download whichever one of these is most appropriate for the screen size for the device (desktop, tablet, or phone):

<div style="width:33%">
<img src=""
     alt="NASA picture of planet Earth"
     srcset=" 300w,
     sizes="33vw" />

You might notice we have also converted the image from png to jpg format, to achieve smaller file sizes. These scaled images are automatically created on-demand, and are then stored in a memory cache so that they are instantly available next time around. The original image file is stored in a directory on the server and is never modified.


Dynamic image operations include:

  • Resize, rotate, flip, crop, and tiling
  • Conversion to different image formats
  • Blur and sharpen
  • Overlays (for adding watermarks)
  • Colorspace conversion
  • ICC / ICM colour profiles (for print publishing)
  • Stripping of image metdata to minimise image file sizes
  • PDF to image conversion

See the imaging user's guide for a full list, or try the online demo.

Image presentation features include:

  • Bookmarkable image URLs
  • Image thumbnail generation
  • HTML/JavaScript libraries
    • Dependency-free with support for Internet Explorer 9 and newer
    • Animated image zooming for HTML5-compliant web browsers and tablets
    • Full-screen image viewing
    • Image carousel / slideshow
    • Image gallery / folder viewer
    • Lazily-loaded images
  • Image publishing wizard
  • Access control via user-groups and folders

Programmatic features include:

  • Image generation templates (a defined group of image operations)
  • A REST API that allows you to securely upload images, generate dynamic images, and perform management and administration

See the API user's guide for more detail.

Management features in the web interface include:

  • File system and image browser
    • Add, rename, move, and delete image files and folders
  • User and group administration
  • Access control / user permissions administration
  • System reports
    • Most popular images (by number of requests, bandwidth, processing time)
    • Server performance charts


JavaScript library - image gallery (incorporating zooming viewer)
Embeddable gallery component

Web interface - folder browse - list view
Folder browse

Web interface - folder browse - grid view
Folder browse

Web interface - image details
Image details view

Web interface - image publisher
Image publisher


QIS depends on the following open source tools and applications:

  • Linux operating system
  • Python 3.4 or above - to run the QIS application code
  • Apache 2.4 - the web server
  • mod_wsgi Apache module - to run the QIS Python application inside Apache
  • ImageMagick - to provide the image processing capabilities
  • Memcached - for caching generated images and frequently accessed data
  • PostgreSQL 9.2 or above - to store image and folder data, users, groups, statistics and permissions

For how these should be installed and configured, see the install guide and the tuning guide.

For low or predictable loads, you can install all of these on one server. A single server installation will easily serve 5 million images per day (60 per second), based on an 8 core CPU, 32GB RAM with a 20GB Memcached instance, mostly scaling and cropping digital camera photographs, and with 95% of requests served from cache.

For high or variable loads, you will want to separate the system into web and storage tiers. Web servers scale better as multiple small servers (rather than one large server), and image processing is typically CPU intensive, therefore it is primarily the web tier that should be scaled out. As an example:

Example web and storage tiers

This system can be scaled up and down on-demand (elastic scaling) by adding or removing web servers at any time. Memcached can run either on a separate server if the network is fast, on one "master" web server, or configured as a cluster across all the permanent web servers. QIS enables consistent hashing when using a Memcached cluster, but you should avoid adding/removing servers to/from the cluster because of the re-distribution of keys that will occur.

The storage tier is harder to scale. Although in general QIS does not use the PostgreSQL database heavily, storing the Postgres data files on a fast disk or SSD is advantageous. The v9.x releases of Postgres have seen some significant performance improvements, so always use the latest version available. PostgreSQL though, can also be clustered and replicated.

Developing, building and running

To run QIS in a development environment, you will need either local or remote Memcached and PostgreSQL servers, ImageMagick installed locally, Python 3.4 or above, and Python development tools pip, wheel, and virtualenv. Development is possible on Linux or on Mac OS X.

Operating system packages

See the install guide for the required system package repositories and packages.

The following development packages (here on a Fedora-based system) are also required in order to build and install the Python libraries:

$ sudo yum install -y gcc gcc-c++ git curl wget make tar zip unzip which \
                   java-1.8.0-openjdk-headless \
                   postgresql-devel openldap-devel openssl-devel libmemcached-devel \
                   python35u-devel python35u-pip
$ sudo pip3.5 install --upgrade pip setuptools wheel virtualenv

Starting development

Get the code, create a virtualenv and install the Python dependencies:

$ git clone
$ cd qis
$ make venv

You will need to request a copy of the qismagick package for your development platform, and install it:

$ . bin/activate
$ pip install qismagick-3.0.0-cp35-cp35m-linux_x86_64.whl

Create 2 empty Postgres databases, qis-cache and qis-mgmt. Create a file in the conf folder, and add settings:

  • DEBUG to True
  • INSTALL_DIR to be the path of your project root
  • Repeat all the *_BASE_DIR values, to apply the new value of INSTALL_DIR

To see the default values and other settings you can override, see the default settings file.

Then run the server in development mode with:

$ make runserver
[checks/installs Python libraries]
2017-03-06 16:11:39,932 qis_37720  INFO     Quru Image Server v3.0.0 engine startup
2017-03-06 16:11:39,934 qis_37720  INFO     Using settings base_settings +
 * Running on (Press CTRL+C to quit)

On first run, the required database tables and default data will be created automatically. Watch the output for the creation of the admin user account, and make a note of the password. If you didn't enable DEBUG mode, look for it in logs/qis.log instead.

While DEBUG is True, the un-minified versions of JavaScript files are served up, and you can make JavaScript changes and refresh your browser to bring them in. When your changes are complete, to minify the JavaScript files for deployment and when DEBUG is False, run:

$ make webpack

To run QIS in production, you will need files:

  • Quru Image Server-3.xx.tar.gz - the main QIS Python web application
  • QIS-libs.tar.gz - the application's Python dependencies, including compiled C extensions as platform-specific binaries
  • and unless your QIS-libs.tar.gz was supplied by Quru, you will also need to request a copy of the qismagick package for your production platform

To generate these files from the development project, run:

$ make distribute
[build script output]
$ ls -l dist/
-rw-r--r--  1 matt  staff   5798089  5 Feb 10:19 QIS-libs.tar.gz
-rw-r--r--  1 matt  staff  54698387  5 Feb 10:19 Quru Image Server-3.0.0.tar.gz

With these files prepared you should then follow the install guide.

Running in Docker

For a much simpler deployment, QIS can be deployed on Docker. There is a docker-compose script that will set up and run almost everything for you. The only extra setup required is a volume on the host in which to store the persistent data, and a couple of environment variables.

See the docker-compose script and the application server image notes for more information.

Version 2

QIS version 2 brought these new features in 2017:

  • Image templates are now stored in the database and managed from the web interface inside QIS
  • Default image values (format, compression, EXIF stripping, etc) are now defined in a default image template, and can be changed from the web interface inside QIS
  • Any image parameter can now have a default value (in the default template)
  • Simpler override rules for image parameters
  • REST API improvements, including programmatic template management
  • Improvements to SVG file support
  • Built-in support for RAW digital camera image formats
  • Faster image serving for logged-in users (and authenticated API callers)
  • Bug fixes to the image publisher
  • Web interface improvements
    • New grid / thumbnail browse view
    • New icons and a more consistent page layout
    • New next/previous image navigation
    • The order of files and folders in the web interface is no longer case sensitive
  • A new JavaScript library for lazily loading images (new in v2.5)
  • Removed the requirement to use the MooTools library on the client side (new in v2.6)
  • Image portfolios (new in v2.7)
    • The creation of a virtual folder of selected images
    • A friendly URL to view the images
    • Download all as a zip file
    • Private, restricted, or public access levels
    • API support currently, user interface support to come in a future release
    • See also the portfolios specification

Since the release of QIS v3, the v2 code (which supports Python 2.6 and 2.7), documentation and build scripts, can be found in the v2 branch but will not receive any new features.

Version 3

QIS v3 is a port of QIS v2.7 to run on Python 3 only. It contains a few tidy-ups, slightly better performance thanks to improvements in Python 3, but otherwise no major new features.

Migrating to v3 is essentially a case of installing new packages and re-installing the application, but for more information see the upgrading guide.


Under consideration for future versions:

  • Image portfolios user interface
    • Addition of "add to basket" while image browsing in the admin interface
    • Addition of portfolios administration to the admin interface
    • Portfolio publishing (to zip) from the admin interface
    • Viewing a portfolio from the gallery and slideshow viewers
  • Improve the image generation architecture for more consistent performance under load
  • Optional long image URL to tiny URL conversion
    • New checkbox in the image publisher
    • Add to REST API
    • Tiny URL admin pages in the web interface
  • Prevent certain image attributes (width, height, overlay) from being overridden
  • Image search and search results
  • Image tags
    • System-defined e.g. assignment of an image category
    • User-defined
    • Tagging a zone or location on an image
    • Searching by tag
  • Modernise the public JavaScript APIs / viewers
    • Use HTML5 data- attributes for automatic initialisation
    • Reduce the number of included files
  • The ability to use an object store (e.g. Amazon S3) for back-end image storage
  • New imaging operations
    • Automatic crop to target dimensions
    • Generate image frames from video files (like Gifify)
    • Enhanced EXIF / XMP support e.g. to set copyright text
    • Automatic file size optimisation (like PNG Crush)
  • Support for new image formats
    • Wide colour / Display P3 profiles
  • Cloud storage integration (Dropbox, Google Drive, ...)
  • Social media integration (Instagram, Flickr, Pinterest, ...)