Image scaling and distribution

Serve scaled and optimized images from the Richie CDN

Richie offers facilities for caching and serving processed and optimized images, with originals hosted on the web.

The images can be resized, cropped and watermarked, if necessary. The original and resulting images are cached to minimize traffic. The resulting images are optimized for minimum download size, while maintaining a high level of visual quality.

Source images are either fetched from an origin agreed in the setup phase, or alternatively using encrypted URLs requested from a dedicated API endpoint.

Setup and some limitations

To use images endpoints, contact Richie for setup. To start using encrypted URLs, you will receive credentials. To start using clear URLs, you will need to provide an origin URL to which source image URLs are relative.

Fully supported source file formats are GIF, JPEG, PNG, WEBP and BMP. SVG is cached and served without processing.

Output format can be agreed when configuring the service, or it can be set for individual requests.

It is also possible to declare a watermark scheme, which means agreeing to draw other images and rectangles on top of source images. The method for requesting watermarks is different for clear relative and encrypted URLs. When using encrypted URLs, non-tamperable watermarks are requested at encryption time. When using clear relative URLs, the watermarks are requested with the image request.


Encryption API

Encrypted image URLs are requested from Encryption API. You will provide clear URLs and whether you want to use watermarks, and Encryption API will return distributable public URLs to the images on Richie CDN. It is also possible to receive feature detection based center points at this phase.

You will need to provide your credentials in HTTP Basic Authorization scheme to use Encryption API.

Input for Encryption API is a JSON document with the following keys. All are optional. Meaningful use will require at least one URL, though.

If a watermark scheme is requested, the query parameter wm in the resulting image URL must be included in all image requests. If the parameter is missing or it has been altered, Images API will refuse to serve the image.

urlsClear image source URLs to encryptList of URLs
asset_urlsClear asset source URLs to encryptList of URLs
include_thumbnail_cropWhether to include feature detection based crop boxes for imagestrue or false
watermark_schemeWatermark scheme name to applyWatermark scheme name

Example request document:

    "include_thumbnail_crop": true,
    "urls": [
    "watermark_scheme": "logos"

Response JSON document will contain encrypted URLs for all the images and possibly crop boxes.

    "processedURLs": {
        "": {
            "encrypted_url": "",
            "properties": {
                "height": 800,
                "width": 1800
            "thumbnail_crop": {
                "center_x": 0,
                "center_y": 0.6

Images API

End users request images from the Images API. Images API is the frontend for serving cached and processed images. The target width and height, result image format and the strategy (mode) to achieve those is specified as query parameters to the Image API.

Image API responds with the processed image ready for display.

Images, other than SVG, can be processed in three different modes. "Fit" will resize the image below the requested dimensions in a bounding box, maintaining the aspect ratio. "Stretch" will change the aspect ratio to fit the requested dimensions exactly, unless source image is smaller. "Crop" will extract an area of the image by either following center_x and center_y parameters, and if they are not set, AI feature detection is performed to find the most interesting part of the image.

SVG images are not processed. GIF and PNG source images requested in GIF or PNG are not processed. These requests are responded to with the source file.

PNG encoded to WEBP is losslessly encoded regardless of the quality setting.

Images are never scaled up.

Source image location is declared in the query path, either as encrypted or relative to the previously agreed origin. All parameters are set in the query string and are optional.

widthFit the image to this widthTargeted width, positive integer
heightFit the image to this heightTargeted height, positive integer
dprApply a multiplier to width, height and size to convert between physical and logical pixels on a HiDPI deviceDevice pixel ratio, positive integer
modeSelect how the image is processed to fit the new dimensions. Also set both width and height, if using "crop" or "stretch" here."fit", "stretch" or "crop"
center_xSpecify a center point for a cropped image with this and center_yDecimal number between 0.0 and 1.0. Horizontal center point relative to image width.
center_ySpecify a center point for a cropped image with this and center_xDecimal number between 0.0 and 1.0. Vertical center point relative to image height.
sizeFit both dimensions of the image to the same size. A shortcut for width=height=size and mode=fit.Maximum width and height as a positive integer
qualitySet quality parameter for JPEG and WEBP encodersInteger between 0 and 100
formatEncode the result in this image format"jpeg", "png" or "webp"
wmUse watermarks according to a schemeWatermark scheme name

Example URL (clear with a relative origin):

Android SDK Changelog