pages can not be separated from a large number of image processing operations. There are many differences between web image processing and image processing for printing and video. Web designers should have a good command of web image processing methods and techniques. In general, the following elements should be considered.
comes in the form of a computer, simple images (such as logos and icons) are preferred in PNG format, while color rich photos must be JPEG. If the color is not large and there is no gradient, you should use the GIF format.
GIF is the most widely used web image format. GIF holds up to 256 colors, almost all images except photos. It also has the ability to generate simple animations and transparent images.
PNG format is relatively new and is also recommended by W3C. PNG-8 can contain up to 256 colors, comparable to GIF; PNG-24 support RGB mode, that can show any color, high quality; PNG-32 in PNG-24 based on the addition of alpha channel, that is, you can set transparent.
JPEG can save about 16 million 700 thousand colors, often used to save photos. But in addition, it’s almost impossible to use JPEG. If the image color is less than 256, or contains a large solid color, the effect of JPEG is not good – in order to obtain high-quality images, the size of the file may increase exponentially.
select image formats should be comprehensive consideration of its scope of use, such as the following detailed expansion of color, transparency, animation and so on. You can compare parameters by using the Export Wizard of Photoshop or Fireworks. The criteria chosen are to ensure acceptable image quality under the premise that documents should be as small as possible.
creates images using the RGB schema instead of the CMYK pattern used for printing. There is no need to consider browser security because almost no one uses a 8 bit display anymore. The choice of color should refer to a uniform standard, such as the VI system. The number and the effect of color is an important factor in determining the format of images, such as color gradient often produce a large number of colors, if you save to GIF will cause distortion, the file size has increased significantly, then you should consider using PNG-24, PNG-32 or JPEG format.
The use of
image vector creation tool making for are saved as PNG format, its size should be determined in the vector drawing tools, into a bitmap will no longer easily on the zoom operation (especially should not amplify operation). It is worth noting that the PNG file created in Fireworks contains editable information such as layers, in which the lines, shapes, and text belong to the vector diagram. Applying such images to a web page should first output operations to compress the file size, and then to lose