Working with images

Understanding image formats

Consider generating outputs. You might create both print-based outputs and online outputs. Typically, print-based outputs include images at a higher resolution (say, 300 dpi) than online outputs (say, 72 dpi). As both types of outputs are created from the same content, it's helpful to be able to designate that a high-resolution image should be used for print and a low-resolution image should be used for online.

CCMS Web makes this possible and simple.

To understand how, consider image objects and image files. The image object is unique to CCMS Web. It's a container for one or more image files. Image files are what you're used to working with—files with extensions such as .png, .jpg, or .svg.

When you create a new image in CCMS Web, you actually create an image object. Even if you import a .png file, for example, CCMS Web creates a new image object and adds the .png file to it.

For each image file in the image object, you then designate its format. The default formats in CCMS Web are

• LowRes
• HiRes
• Source

You can add other formats if needed.

The order in which formats are defined in the configuration is important. It determines which format is automatically designated as the default for image objects. It also affects how the format that's selected for image files when you add them to a new image object.

If you have both a high-resolution and a low-resolution version of an image, you create an image object, and add both files to it. You select the format that matches the image.

When you reference an image from a topic, you actually reference the image object, not individual image files. While this is difficult to see in a DRM environment due to the use of keys, if you happen to work in a Standard environment, you can look at the XML source for a topic and you'll see that the image element references something like abc1234567890987.image rather than abc1234567890987.png.

(The .image extension is unique to CCMS Web.)

When you generate outputs, the Output Generator is set up to select a specific format based on the output type. For example, if you are generating a PDF, the Output Generator selects the image file designated as HiRes from within the image object. If you are generating XHTML, the Output Generator selects the image file designated as LowRes from within the image object.

In this way, you can automatically use the correct resolution for your output without having to insert multiple images and use conditions and a ditaval to select the correct one.

What happens if the output type specifies HiRes but an image object doesn't include an image with that format? That is no problem; the Output Generator selects the format that is present. If an image object only contains a LowRes image, all outputs use that one.

Understanding image types

CCMS Web provides a built-in mechanism to help you classify image objects according to type. An image object's type does not affect how it behaves in any way; it is simply a piece of information that helps you search more specifically for certain types of images.

For example, if you want to insert an image in a topic, and you know it's a diagram, you can select "Diagram" as the type on the Insert Image dialog to narrow the search.

A few image types are provided in the default configuration but you can add as many as you need to categorize your image objects.

The order in which types are defined in the configuration is meaningful. The type defined first is the default entry in the Type field when creating a new image object.

What image file types does CCMS Web support?

CCMS Web can theoretically support any image file type as it simply stores the image files and provides them to the Output Generator for output.

CCMS Web supports these common image file types, but you can add others to your configuration:

• BMP
• EPS
• GIF
• JPEG
• PNG
• SVG
• TIF