Image Editing 101: A Guide to Image Formats and File Types

by Caroline Mercurio on September 19, 2014 No comments

Image formats are the standardized data structures that determine how a computer processes, displays, and stores digital images. The files themselves are made up of rasterized digital data. Image files may store data in compressed, uncompressed, or vector formats. Once a computer rasterizes it, an image will become a pixel grid, and each pixel will have a number of bits that designate the color and the depth of color on the device displaying the image.

Image file types store information on computers to allow for editing, display, or reading by one specific program. Ascertain the file type by glancing at the file name’s last three letters. This is the file extension, and different programs use different extensions to save files.

Common File Types

Some of the most common graphics file types are JPEG (with the extension .jpg), TIFF (with the extension .tif), and bitmap (with the extension .bmp). Some of today’s digital cameras can also save photographs in RAW format. This is an uncompressed format without any effects yet applied.

Lossy vs. Lossless Compression

The terms “lossy” and “lossless” apply to compression. Lossless algorithms do not discard any information. Instead, they look for efficient ways in which to represent images without compromises when it comes to accuracy. Lossy algorithms will accept some degree of degradation of the images to achieve files of smaller sizes. For more information about vector vs. raster images.

JPEG files are optimal for photos and similar images containing many colors. They achieve high compression ratios without much loss of image quality. JPEGs work by making analyses of images you are editing and discarding the things your eye is least likely to notice. JPEG compression is adjustable so that you can edit and save affordable quality content from

TIFF files are flexible and may have lossy or lossless compression. The details of the algorithms used are part of the files. The TIFF format usually serves as storage for lossless images with no compression applied. Graphics programs using TIFF files do not compress, so the file size may become quite large.

PNG files are another lossless format for storage. Unlike TIFF usage, PNG looks for compressible image patterns. The compression is reversible, so it can recover the original image precisely.

GIF images have compression and are not as kind to the look of the images. They create tables including 256 colors or less from 16 million colors in a pool. If your images have less than 256 colors, GIFs will render your images exactly. If your image has many more colors, they will approximate all colors within the 256-color palette.

“PSD” format is only used by graphics programs. Photoshop files have this extension, and Paint Shop Pro files are “PSP” files.

PDF stands for “portable document format.” Adobe Systems designed this format, which has become the standard for exchanging electronic documents.

EPS, standing for Encapsulated Post-Script are vector images that can be resized to any size, and can be printed while keeping an amazing quality.

Make sure to take a look at our articles of “How to Vectorize an Image” and “How to Rasterize an Image”.

Caroline MercurioImage Editing 101: A Guide to Image Formats and File Types

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