Operation Manual

354

Web graphics

Last updated 9/13/2015

More Help topics

Optimized file formats for the web

Use the Adobe Color Picker

Optimize as GIF or PNG-8 format

Add a browser to the Preview In menu

Optimizing images for the PNG-24 format

About the PNG-24 format

The PNG-24 format supports 24-bit color. Like the JPEG format, PNG-24 preserves the subtle variations in brightness

and hue found in photographs. Like the GIF and PNG-8 formats, PNG-24 preserves sharp details like those in line art,

logos, or type.

The PNG-24 format uses the same lossless compression method as the PNG-8 format. For that reason, PNG-24 files

are usually larger than JPEG files of the same image. You may want to avoid PNG-24 format when you are distributing

your image to a wide audience.

In addition to supporting background transparency and background matting, the PNG-24 format supports multilevel

transparency. You can have up to 256 degrees of transparency from opaque to completely transparent, so you can blend

the edges of an image smoothly with any background color. However, not all browsers support multilevel transparency.

Optimize as PNG-24

PNG-24 format is suitable for compressing photographs. However, PNG-24 files are often much larger than JPEG files

of the same image. PNG-24 format is recommended only when you work with an image that includes multiple levels

of partial transparency.

1 Open an image and choose File > Save For Web.

2 Choose PNG-24 for the optimization format.

3 Select Interlaced to create an image that is displayed at low-resolution in a browser while the full-resolution image

is downloading. Interlacing can make downloading time seem shorter and gives viewers feedback that downloading

is in progress.

4 If the image contains transparency, select Transparency to preserve transparent pixels; deselect Transparency to fill

fully and partially transparent pixels with the Matte color.

5 To save your optimized image, click OK. In the Save Optimized As dialog box, type a filename, and click Save.