While Photoshop comes with many different features to tackle, many people often come up short when asked what image formats Photoshop will open or save in. How do you know which one to use, and what are the advantages or disadvantages of each?

The odds are in your favor as Photoshop has the ability to open and save a variety of graphic files. Here are some of the more popular formats.

One thing to remember is that when you open an image file other than a Photoshop one, the image will default to the background layer.

1) .psd, .pdd, .eps:

These are Photoshop files. This format saves all of the information found in all of the layers. This format works best if you are going to continue to work with a picture. A downside can be that the file size may be quite large. You should save your work in the most recent Photoshop format available. An example would be is you have Photoshop CS and are sent a Photoshop 7 file, you would want to save it as a Photoshop CS file to maintain any elements that may not be supported in Photoshop 7.

.jpg, .jpeg .jpe

This format compresses the images, so that information (details and colour subtleties) are lost. You can choose how much you want to compress the image. Good format for use on the web. Small file sizes. Millions of colours.

tif, .tiff

Common in use with early scanners. Will produce high quality images, but very large files. Not for use on the web.

4) .gif

This format can be pronounced both \”Gif\” and \”Jif\”. This file is one of the most popular for web graphics as it loads quickly. Has an 8 bit format (256 colors max.). It can support transparent color and animation.

5) .png

For use on the web, this is a new format that is meant to replace both gif and jpeg. Files are compressed, millions of colors and transparencies supported. It compress in a different way than jpeg, and has advanced possibilities, such as alpha channel (opaque or partly transparent colors). The downfall is that Internet Explorer doesn\’t support these. In 8 bit (256 colors) mode it compresses better than gif.

6) .bmp

This is a windows bitmapped image. It is used by Microsoft Windows applications and provides good quality but large file size. Not for use on the web.

7) .wmf – Windows MetaFile

Windows MetaFile. Useful for clipart, and can be used to make large area, small sized background files.

.pcx

Older general purpose format. Practically obsolete now. Not for use on the web.

.psp

Internal format for Paint Shop Pro and is useful if you want to swap files between these two programs.

.pcd

Kodak PhotoCD format, used with Photo Developing – although most photo processors will save your photos as jpegs if you ask them to.

.pdf

Portable Document File. Adobe\’s file system that allows electronic cross platform sharing of documents.

Now the question: What is the best format for web graphics: gif or jpeg?

The answer is pretty easygifs for drawings and jpeg for photos. In more depth, use gifs for diagrams, line drawings, illustrations, and images that contain large areas of flat color, and jpegs for photographs and images with continuous color tones. The jpeg format has a great compression rate, but compression diminishes the quality of the image, so it\’s best to experiment with the tools in Image Ready until you have the optimal quality/file size. The gif format, comparatively, has a smaller file size, but a narrow range of colors.