You might find yourself wondering what image file formats Photoshop will open or save in. What are the advantages or disadvantages of each?
Simply put, Photoshop has the ability to open and save a variety of graphic files. Let's take a look at the more popular ones.
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 - Photoshop File
Photoshop File. This format preserves the information in all the layers. If you're going to continue working with a picture, this is the best format to use. File size can be quite large, however. Note: It is advisable to save your work in the most up to date Photoshop format available. For example: if you have Photoshop CS and are sent a Photoshop 7 file, you should save it as a Photoshop CS file to preserve any elements that may not be supported by Photoshop 7.
2) .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 - Pronounced both "Gif" and "Jif"
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
This is a new format for use on the web that is intended to replace both gif and jpeg with its ability to compress, have millions of colors, and support transparencies. It compresses differently from jpeg, and has advanced possibilities, such as alpha channel (opaque or partly transparent colors). The only problem is that Internet Explorer does not support this format. In 8 bit (256 colors) mode it compresses better than gif.
6) .bmp - Windows Bitmapped Image
Windows bitmapped image. Used by Microsoft Windows applications. Good quality, large file size. Not for use on the web.
.wmf
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.
9) .psp
Internal format for Paint Shop Pro, useful if you want to swap files between these two applications.
.pcd
Kodak PhotoCD format, used with Photo Developing - although most photo processors will save your photos as jpegs if you ask them to.
11) .pdf - Portable Document File
Portable Document File. Adobe's file system that allows electronic cross platform sharing of documents.
So what's the best format for web graphics: gif or jpeg?
Easy way to remember is that gifs are typically used for drawings and jpegs for photos. Use gifs for diagrams, illustrations, line drawings and images with large areas of flat color. Jpeg should be used for photographs and images with continuous color tones. While the jpeg has an excellent compression rate, the compression lowers the quality of the image so try out some of the tools in Image Ready to find the optimal quality/file size. The gif format in comparison has a smaller file size but a limited range of colors.