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File Types
JPEG, TIFF, PSD, PNG, GIF… Why do we need so many of these file formats? This article aims to explain some of the particulars of the more popular file formats, and why we need more than one.
Basics
There are two types of file formats – compressed, and uncompressed. Compression is basically when the computer “cheats”, and tries to make a file smaller than it really is. There are two types of compression – lossy, and lossless. Lossy compression may work in several manners, but typically looks at a picture, and decides what pieces of information it can throw away. It will then attempt to put the picture back together, and this often causes the “artifacts” you see on some pictures. There are various levels of lossy compression. The first picture is a file with high compression, and the second one with low compression.
Note the artifacts in the first image, particularly around the text in the watermark (upper right corner) and in the background.
Lossless compression merely works to organize the data in a picture in a more space-efficient order.
File Types
JPEG
The most commonly used file format for pictures. It is used both for display (such as pictures on the Internet) and a format cameras use to save pictures.
Pros – Universally viewable, small file sizes
Cons – Lossy compression, limited color depth
PNG
This is a relatively new file format, and is meant to replace JPEG. It is also a form of lossy compression, but uses a more efficient compression formula than JPEG. This means smaller file sizes, but with a higher quality than JPEG.
Pros – Gaining more acceptance, small files sizes
Cons – Not as widely accepted as JPEG, limited color depth
GIF
Another lossy compression format, GIF is commonly used for logos and clip-art type images – not usually for photos.
Pros – Small files sizes, widely accepted
Cons – Not meant for photos, compression format not overly efficient
PSD
Adobe’s Photoshop file format is widely used for professional applications, as well as editing.
Pros – No compression, widely used
Cons – Large file sizes, not universally editable across different software
TIFF
Another non-compressed format, TIFF is similar to the PSD format by Photoshop, but is more universal. Nearly every image editing program can open TIFF files.
Pros – No compression, universally accessible
Cons – Larger than the same version of a file in PSD format
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