A large number of
image file formats
An Image file format is a file format for a digital image. There are many formats that can be used, such as JPEG, PNG, and GIF. Most formats up until 2022 were for storing 2D images, not 3D ones. The data stored in an image file format may b ...
are available for storing graphical data, and, consequently, there are a number of issues associated with
converting from one image format to another, most notably loss of image detail.
Software compatibility
Many image formats are native to one specific graphics application and are not offered as an export option in other software, due to proprietary considerations. An example of this is
Adobe Photoshop's native PSD-format(Prevention of Significant Deterioration), which cannot be opened in less sophisticated programs for image viewing or editing, such as
Microsoft Paint.
Most image editing software is capable of importing and exporting in a variety of formats though, and a number of dedicated image converters exist.
Loss due to compression
Besides uncompressed formats and
lossless compression
Lossless compression is a class of data compression that allows the original data to be perfectly reconstructed from the compressed data with no loss of information. Lossless compression is possible because most real-world data exhibits statistic ...
formats that can usually be interconverted without any loss of detail, there are compressed formats such as
JPEG
JPEG ( ) is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and im ...
, which lose detail on nearly every compress. While a conversion from a compressed to an uncompressed format is in general without loss, this is not true the other way around. Even a compressed-uncompressed-compressed round trip without any image manipulation may incur some loss of detail.
Loss due to format change
Like any
resampling operation, changing image size and
bit depth are lossy in all cases of
downsampling, such as 30-bit to 24-bit or 24-bit to 8-bit
palette
Palette may refer to:
* Cosmetic palette, an archaeological form
* Palette, another name for a color scheme
* Palette (painting), a wooden board used for mixing colors for a painting
** Palette knife, an implement for painting
* Palette (company), ...
-based images. While increasing bit depth is usually lossless, increasing image size can introduce
aliasing or other undesired artifacts.
RAW images
More expensive
digital cameras usually offer the option to shoot in
Raw image format. RAW is not a standardized format, in fact, RAW-formats even differ between camera models from the same vendor. Data in a RAW-file is structured according to the
Bayer filter's pattern in cameras that use a single
image sensor.
Debayering, the process of obtaining bitmap data from a RAW-image is always a lossy operation. In addition, some downsampling is always performed, again reducing image information.
See also
*
Comparison of graphics file formats
*
Image organizer
*
Image viewer
Graphics standards
File conversion software
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