People often ask me: What image file formats will Photoshop open or save in? What are advantages/disadvantages?
Photoshop has capability to open and save many different graphic files. Here are some of most popular ones.
Note: When you open an image file other than a Photoshop one, that image will default to background layer.
.psd, .pdd, .eps Photoshop File. This format preserves information in all layers. If you're going to continue working with a picture, this is best format to use. File size can be quite large, however. Note: It is advisable to save your work in 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.
.jpg, .jpeg .jpe This format compresses images, so that information (details and colour subtleties) are lost. You can choose how much you want to compress image. Good format for use on 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 web.
.gif Pronounced both "Gif" and "Jif", this file is one of most popular for web graphics as it loads quickly. 8 bit format (256 colours max.). It has possibilities for transparent colour and animation.
.png New format for use on web that is intended to replace both gif and jpeg. Compressed, millions of colours, transparencies. It compress in a different way than jpeg, and has advanced possibilities, such as alpha channel (opaque or partly transparent colours). The only trouble is: Internet Explorer doesn't support these! In 8 bit (256 colours) mode it compresses better than gif.