Supported Image File Formats
Image file formats are standardized means of organizing and storing images. Image files are composed of either pixel or vector (geometric) data. So image formats are divided into three groups: raster formats, vector formats and metafile formats (include both vector and bitmap components).
Raster formats store images as bitmap that is a data structure representing a generally rectangular grid of pixels, or points of color. A bitmap is technically characterized by the width and height of the image in pixels and by the number of bits per pixel.
The greater the number of rows and columns is, the greater the image resolution is, and the larger the file is. Also, each pixel of an image increases in size when its color depth increases — an 8-bit pixel (1 byte) stores 256 colors, a 24-bit pixel (3 bytes) stores 16 million colors, the latter is known as truecolor. Image compression uses algorithms to decrease the size of a file.
There are two types of image file compression algorithms: lossless and lossy. Lossless compression algorithms reduce file size without losing image quality, though they are not compressed into a file with the same small size as a lossy compression file. When image quality is valued above file size, lossless algorithms are typically chosen. Lossy compression algorithms take advantage of the inherent limitations of the human eye and discard invisible information.
Most of the commonly used raster image file and metafile formats are supported by AVS Photo Editor:
Microsoft Windows OS
Widely accepted |
|
Typically uncompressed, hence large, best image quality |
+ / + |
| Microsoft Windows OS |
One or more small images at multiple sizes and color depths |
|
+ / - |
| Microsoft Windows OS |
Layout of a printed page containing text, objects and images (line-art, illustrations, content created in drawing or presentation applications) |
WMF is a 16-bit format, EMF is a newer 32-bit version |
+ / + |
- -In digital cameras and other photographic image capture devices
- -For storing and transmitting photographic images on the WWW
- -Best for the final distribution of photographic images
|
|
- -Lossy format
8 bits per color (red, green, blue) for a 24-bit total - -Generational degradation when repeatedly edited and saved
- -Small files
|
+ / + |
- -Suitable for storing graphics with relatively few colors such as simple diagrams, shapes, logos and cartoon style images
- -Widely used to provide image animation effects
|
|
- -Limited to an 8-bit palette, or 256 colors
- -Lossless compression that is more effective when large areas have a single color, and ineffective for detailed images or dithered 1 images
- -Small files
|
+ / + |
- -Best for WWW
- -Fully streamable with a progressive display option
- -Best suited for editing pictures
|
- -Gamma and chromaticity data for improved color matching on heterogeneous platforms
- -Indexed-color, grayscale, and truecolor images are supported
|
Lossless |
+ / + |
| Not widely supported by web browsers, but widely accepted as a photographic file standard in printing industry |
- -Size, definition, image-data arrangement, applied image compression
- -Can handle device-specific color spaces, such as the CMYK
|
Lossy and lossless (if lossless, editing and re-saving without losing image quality) |
+ / + |
| In digital cameras |
- -Date and time information
- -Camera settings
- -Thumbnails for previewing the picture
- -Descriptions
- -Copyright information
|
Lossy and lossless depending on the file format used (JPEG, TIFF Rev. 6.0, and RIFF WAV ) |
+ / + |
| Used for graphic data storage and exchange in desktop publishing system |
Capable of storing up to 256 colors |
Compressed (lossless Run-Length Encoding) and uncompressed |
+ / + |
| The most universally supported 24-bit file format for PC applications |
- -Capable of storing image data with color depth of 1–32 bits per pixel
- -Supports color maps 2, alpha channel, gamma value, postage stamp image, textual information, and developer-definable data
|
Compressed (lossless Run-Length Encoding) and uncompressed |
+ / + |
| Widely used and distributed particularly on systems running on the Unix OS |
- -Capable of storing black-and-white, greyscale, and color bitmapped data of any color depth
- -Use of color maps 2 supported
|
Compressed (lossless Run-Length Encoding) and uncompressed |
+ / + |
| In digital equipment (like cameras or film scanners) as 'digital negatives' |
- -File header,
- -Camera sensor metadata,
- -Image metadata,
- -Image thumbnail
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- -Higher image quality,
- -Finer conversion parameter setting,
- -Selectable color space,
- -More information contained in files,
- -Large transformations of the data
|
+ / - |
1 - Dithering is a technique used in computer graphics to create the illusion of color depth in images with a limited color palette. In a dithered image, colors not available in the palette are approximated by a diffusion of colored pixels from within the available palette. The human eye perceives the diffusion as a mixture of the colors within it.
2 - Color map is a matrix of real numbers between 0.0 and 1.0, where each row is an RGB vector that defines one color.
3 - RAW file formats are used by different camera manufacturers as their own proprietary and typically undocumented formats, which can vary from model to model: .crw .cr2 (Canon), .dng (Adobe), .mef (Mamiya), .nef (Nikon), .orf (Olympus), .arw (Sony). The purpose is to save with minimum loss of information the data that are obtained from the sensor, and the conditions surrounding the capturing of the image (the metadata). These files are not yet processed and therefore are not ready to be used with a bitmap graphics editor or printed. Normally, the image is processed by a raw converter where precise adjustments can be made before conversion to a "positive" file format such as TIFF or JPEG for storage, printing, or further manipulation, which often encodes the image in a device-dependent color space.