Image Formats

Image Files | Image Formats

Image Formats

Unfortunately, image files come in a variety of formats, so Web browsers must either be able to deal with many formats, or you must have the capability to convert easily among these formats.
Browsers generally display images in two different ways: (1) in-line, using the browser itself, and (2) externally, in a separate window, often with the aid of a "Helper Application". The adjacent figure is an example of an in-line image; here is an example of an external image.

Displaying In-Line Images

The popular browsers support only a limited number of graphics file formats for inline images, with the most common being GIF and JPEG. For graphics created on a PC, files can often be saved in a BMP format, but not GIF or JPEG. You don't need to worry about the technical differences between BMP and JPEG and GIF formats; You only need to know that there are programs available that will convert from the BMP format to either GIF or JPEG. So if you are using graphics software on a PC to create artwork that you want to put on a Web page, you will probably also need access to one of these format conversion programs. More on this later.
Displaying External Images

Web browsers are more flexible in the formats they can display as external images because these are often displayed using separate "Helper Applications" that can be tailored to deal with a particular format. Provided a program exists that can display the format and runs on your computer, it is likely that the browser can be configured to display that format by launching the helper application.
For example, it is very common in scientific and technical settings to encounter images written in Postscript format (Postscript files commonly have a .ps or .eps extension in their names). A browser like Netscape cannot display Postscript directly, but it can be configured such that when it encounters a Postscript file it launches a helper application that displays the file in a separate window.


			Image Files \| Image Formats
		Image Formats Unfortunately, image files come in a variety of formats, so Web browsers must either be able to deal with many formats, or you must have the capability to convert easily among these formats. Browsers generally display images in two different ways: (1) in-line, using the browser itself, and (2) externally, in a separate window, often with the aid of a "Helper Application". The adjacent figure is an example of an in-line image; here is an example of an external image. Displaying In-Line Images The popular browsers support only a limited number of graphics file formats for inline images, with the most common being GIF and JPEG. For graphics created on a PC, files can often be saved in a BMP format, but not GIF or JPEG. You don't need to worry about the technical differences between BMP and JPEG and GIF formats; You only need to know that there are programs available that will convert from the BMP format to either GIF or JPEG. So if you are using graphics software on a PC to create artwork that you want to put on a Web page, you will probably also need access to one of these format conversion programs. More on this later. Displaying External Images Web browsers are more flexible in the formats they can display as external images because these are often displayed using separate "Helper Applications" that can be tailored to deal with a particular format. Provided a program exists that can display the format and runs on your computer, it is likely that the browser can be configured to display that format by launching the helper application. For example, it is very common in scientific and technical settings to encounter images written in Postscript format (Postscript files commonly have a .ps or .eps extension in their names). A browser like `Netscape` cannot display Postscript directly, but it can be configured such that when it encounters a Postscript file it launches a helper application that displays the file in a separate window.