Configure Image and Quality Settings
You can now deliver high quality images without worrying about byte size or bloated web pages. Image and Video Manager automatically creates and delivers optimized images with the correct resolution and format based on your customer's device.
Before you begin
The Event Viewer in Akamai Control Center records Image and Video Manager - Policy Manager events and details.
- The default policy: Image and Video Manager applies the default policy unless a request includes a parameter indicating a valid custom policy name. The default policy contains the default settings that determine how Image and Video Manager generates derivatives for the policy set. The default policy appears in the Policies section after you after you open Policy Manager, select a contract and a policy set, and click Manage Policies. You can edit the default policy.
- A custom policy: You can create and edit custom policies for images to apply different quality settings and artistic transformations. Once you've defined your policies, use Image and Video Manager parameters to associate the correct policy to each image or video request.
To configure your policy settings:
- Go to .
- Select your contract in the Contract field.
- Select a policy set name in the Policy Set Namefield. You should select the policy set name that you specified in Connect Your Images. A policy set is a collection of policies grouped in a way that makes sense for your organization. For example, you might organize your policies according to your hostnames. That would allow you to apply policies to all images at a particular hostname.
A list of policies appears in the Policies section.
If you want to edit the default
policy, select the Actions menu next to it and click View/Edit Staging/Production
Policy. If you want to create a new custom policy, click
Policy. If you want to edit a custom policy, select the Actions
menu next to it and click View/Edit Staging/Production
The Image Policy Editor appears. In the Workflow section, you can set up the order in which Image and Video Manager applies image and quality settings, and transformations and conditions, when it uses this policy to optimize an image.
- Select Image and Quality and Settings and then Derivative Quality.
Select one of the following
under Derivative Image
Quality to specify the visual quality of images for your policy.
Lowering quality reduces file size and improves performance.
- Static. Allows Image and Video Manager to choose the optimal quality for your image. Image and Video Manager automatically uses the system default value of 85. You can select Fixed Value and change the value to any number you choose. The higher the number you choose, the higher the quality level of images using this policy. If you want to set a fixed value, select Fixed Value and enter a number for the quality level you want to use.
Quality. Allows you to select a qualitative category
descriptor. Perceptual quality lightens the weight of your images while
maintaining the best visual quality by intelligently calculating and
applying a precise degree of compression for the maximum level of byte
reduction that is imperceptible to the human eye. To learn how to
preview your images with different perceptual quality settings, see
Create Perceptual Quality Previews.
- If you select High, you get the highest quality level, but the lowest byte reduction.
- If you select Medium/High that means one thing for an all black image and another for a color portrait. Image and Video Manager then creates quality levels of 50, 54, 75, 64, and so on, because the way it analyzes each image pixel by pixel and determines what amount of change is appropriate given the qualitative measure you selected.
- If you select Medium Low, you get a lower quality level, but high byte reduction. By default, Image and Video Manager uses a perceptual quality level of medium high.
- If you select Low, you get the lowest quality level, but the highest byte reduction.
You can optionally set the Perceptual Quality Minimum Threshold, which is an advanced setting that ensures a minimum quality level for images using perceptual quality. When you set a perceptual quality level, Image and Video Manager automatically displays images of an appropriate quality and visual similarity to the original image based on that level. Set a fixed value in this field when you do not want higher levels of compression and byte savings even if the perceptual quality setting you specified would consider the compressed image to be acceptably visually similar.
Optionally select Fixed Value
and enter a number between 1 and one hundred in Quality Value Override for
Slow Connections to set the quality level when Image and Video
Manager detects images accessed by users with slow connections. This reduces
file sizes and improves load times. When you set a fixed value in this field and
Image and Video Manager detects a slow connection, it displays images with the
specified quality instead of the value you set for static or perceptual quality.
Specifying a lower value helps users with slow connections browse your site with
reduced load times without impacting the quality of images displayed to users
with standard connections. By default Quality Value Override for Slow
Connections is disabled. The default fixed value is 50.
This setting also applies to mobile devices when the Save-Data header is enabled. Mobile devices in data saving mode receive the lower quality image even if the network connection is not slow.
- Select Derivative Image Widths and for each derivative image, enter the width in pixels in the field. Separate widths with commas. A policy can generate multiple derivative images of different sizes. If the Derivative Image Widths field is empty, Image and Video Manager applies these defaults: 5000, 2048, 1024, 640, and 320. When Image and Video Manager receives a request for an image with an Image and Video Manager policy, it serves the size that best suits the requesting device’s display.