Image File Formats
Written by Abin Alex and Anu Joseph.
Abstract
An image file format is a way of storing picture data. Camera RAW formats differ by maker, such as NEF for Nikon, CR3 for Canon and ARW for Sony, and no single open standard covers them all, while shared formats such as JPEG, PNG, TIFF, WebP and HEIF are made for sharing, print and the web. This guide separates compressed from uncompressed files, lists the RAW formats of each camera company and of cinema cameras, and explains DNG, Apple ProRAW and the common web formats. It ends with guidance on which format to use for which job.
Keywords: image file formats; RAW; JPEG; TIFF; HEIF
- What is an image file format?
- What are compressed and uncompressed image files?
- What are the RAW formats of each camera company?
- What is DNG and Apple ProRAW?
- What are JPEG and JPG?
- What are PNG, GIF, TIFF and BMP?
- What are WebP, HEIF, HEIC and AVIF?
- What are the RAW formats in cinema cameras?
- Which format should you use?
What is an image file format?
Short answer. A file format is a set of rules for storing picture data. Formats differ in compression, bit depth, colour and what they are meant for.
- Image types are based on the compression used to reduce the file size.
- Lossless compression keeps every detail and can be reversed exactly. Lossy compression throws away some data to make files smaller.
- A raster image is a grid of pixels. A vector image is stored as lines and curves and can be scaled to any size.
- A file extension is the letters after the dot in a file name, such as .jpg. The extension shows the format but does not change it.
- The Digital Image Pipeline guide explains how the camera makes these files.
Cham tipAsk three questions about any format: lossy or lossless, how many bits, who can open it.
Cham taskList the file formats your camera can record and mark each lossy or lossless.
Check yourself: What does lossless mean?
The file can be restored exactly, with no detail lost.
What are compressed and uncompressed image files?
Short answer. Compression makes a file smaller. Lossless compression keeps every detail and can be reversed exactly. Lossy compression discards some data for a much smaller file. Uncompressed files store everything and are the largest.
- Uncompressed: the data is stored as it is. BMP is uncompressed. Some cameras can record uncompressed RAW, which gives the largest RAW files.
- Lossless compressed: the file is made smaller, and the original data can be restored exactly. PNG is lossless, and TIFF is usually lossless. Many cameras offer lossless compressed RAW.
- Lossy compressed: some data is thrown away for good. JPEG is lossy. Some cameras also offer a lossy compressed RAW with smaller files and a small loss of data.
- Camera menus name these options differently by maker. Look for words such as uncompressed, lossless compressed, compressed or high efficiency in the RAW setting.
- Quality settings in JPEG change the amount of compression. A lower quality gives a smaller file with more visible blocks and ringing around edges.
- File size can be estimated. A 24 MP RAW file with one 14-bit value per pixel holds about 24 000 000 × 14 ÷ 8 = 42 MB before any compression. A 24 MP image as 8-bit RGB holds 24 000 000 × 3 = 72 MB uncompressed. Real files are smaller when compressed.
| Kind | Data lost? | Examples | File size |
|---|---|---|---|
| Uncompressed | No | BMP, uncompressed RAW, uncompressed TIFF | Largest |
| Lossless compressed | No, restored exactly | PNG, TIFF with lossless compression, lossless RAW, DNG | Medium |
| Lossy compressed | Yes, for good | JPEG, WebP lossy, HEIC, lossy RAW | Smallest |
Table 1. Uncompressed, lossless and lossy files.
| Format | Compression type |
|---|---|
| RAW | Uncompressed, lossless or lossy, set in the camera menu |
| JPEG / JPG | Lossy |
| PNG | Lossless |
| TIFF | Uncompressed or lossless (lossy variants exist) |
| GIF | Lossless, 256 colours |
| WebP | Lossy or lossless |
| HEIF / HEIC / AVIF | Usually lossy, lossless modes exist |
| BMP | Uncompressed |
Table 2. Compression type by format.
Cham tipLossless can be undone exactly. Lossy cannot. Keep the master lossless.
Cham taskSet your camera to uncompressed or lossless RAW, then to a compressed RAW option if it has one. Compare file sizes of the same scene.
Check yourself: Which loses data, lossless or lossy compression?
Lossy compression.
What are the RAW formats of each camera company?
Short answer. Each major camera maker uses its own RAW format with its own extension. Makers publish little about them, and the formats are largely undocumented (Library of Congress, 2023).
- The Library of Congress treats camera raw formats as a group of proprietary formats, not one format (Library of Congress, 2023).
- The same maker can change format over time. For example, Canon used CRW, then CR2, and newer bodies use CR3 (Library of Congress, 2023) (FileInfo, n.d.).
- Most makers do not publish an official long form for the extension. Where the table says so, treat the extension as a label only. The other meanings are the commonly used names.
- Some makers also record DNG, so check your camera menu.
| Maker | Extension | Name meaning | Notes |
|---|---|---|---|
| Canon | CRW | Canon RAW (original format) | Older cameras; based on CIFF |
| Canon | CR2 | Canon RAW version 2 | TIFF-based; many EOS cameras |
| Canon | CR3 | Canon RAW version 3 | Newer Canon cameras |
| Nikon | NEF | Nikon Electronic Format | Standard Nikon RAW |
| Nikon | NRW | No official long form published | Some Coolpix cameras |
| Sony | ARW | Alpha RAW | Alpha cameras |
| Sony | SRF / SR2 | No official long form published | Older models |
| Fujifilm | RAF | RAW Fuji Format | All Fujifilm cameras |
| Olympus / OM System | ORF | Olympus Raw Format | Olympus and OM System |
| Panasonic | RW2 | No official long form published | Lumix cameras |
| Pentax / Ricoh | PEF | Pentax Electronic Format | Also records DNG |
| Leica | DNG / RWL | DNG: Digital Negative. RWL: No official long form published | Many Leica models use DNG |
| Hasselblad | 3FR / FFF | No official long form published | Medium format |
| Phase One | IIQ | Intelligent Image Quality | Medium format backs |
| Sigma | X3F | Foveon X3 File | Foveon sensor cameras |
| Samsung | SRW | No official long form published | Older Samsung cameras |
| Kodak | DCR / KDC | No official long form published | Older Kodak cameras |
| Minolta | MRW | No official long form published | Older Minolta cameras |
| Epson | ERF | No official long form published | Older Epson cameras |
| Mamiya | MEF | No official long form published | Medium format |
| GoPro | GPR | No official long form published | Action cameras |
| DJI | DNG | Digital Negative | Many DJI drones |
Table 3. RAW formats by camera maker. Extensions follow the Library of Congress and FileInfo lists; name meanings are commonly used names, not official statements (Library of Congress, 2023) (FileInfo, n.d.).
Cham tipKeep the maker's extension. Do not rename a file to change its format.
Cham taskFind the RAW extension of your own camera and which software opens it.
Check yourself: Which maker uses the NEF extension?
Nikon.
What is DNG and Apple ProRAW?
Short answer. DNG, short for Digital Negative, is a RAW format made by Adobe to be a standard way to archive RAW images (FileInfo, n.d.).
- DNG was designed as a standardised format for archiving RAW images and many programs support it (FileInfo, n.d.).
- Some cameras, drones and phones record DNG directly. Other RAW files can be converted to DNG.
- Apple ProRAW is a RAW type on selected iPhone Pro models that combines sensor data with the phone's processing and is saved as a DNG file.
- DNG helps long-term access because the format is documented and widely read, but converting does not improve the picture.
Cham tipKeep the original RAW as well as any DNG copy.
Cham taskConvert one RAW file to DNG in your editing software. Compare the file sizes.
Check yourself: What does DNG stand for?
Digital Negative.
What are JPEG and JPG?
Short answer. JPEG, short for Joint Photographic Experts Group, is a lossy format for photographs. JPG is the same format with a shorter extension.
- JPEG is optimised for photographs and continuous-tone images with many colours, and it reaches high compression.
- JPEG and JPG are the same format. Older systems allowed only three letters in an extension, so .jpg became common.
- JPEG stores 8 bits per channel, about 16.8 million colours.
- Each time you save a JPEG again at a lower quality, you lose more data. Edit from the RAW or a lossless copy, and export JPEG last.
- JPEG does not support transparency.
Cham tipExport JPEG once, from the master file.
Cham taskSave the same photo at quality 100, 70 and 30. Compare the sizes and look at the edges.
Check yourself: Is JPG different from JPEG?
No. They are the same format with different extension spellings.
What are PNG, GIF, TIFF and BMP?
Short answer. PNG and TIFF are usually lossless. GIF limits colours to 256. BMP is an uncompressed format from Microsoft.
- PNG, Portable Network Graphics, is lossless and exactly reversible. It supports transparency and suits graphics, logos and screenshots.
- GIF, Graphics Interchange Format, uses a table of up to 256 colours. It is used for simple graphics and short animations.
- TIFF, Tagged Image File Format, is flexible and usually lossless, so files are large. It is common in print and archive work.
- BMP, Bitmap, is an uncompressed format invented by Microsoft.
| Format | Full form | Compression | Transparency | Typical use |
|---|---|---|---|---|
| PNG | Portable Network Graphics | Lossless | Yes | Logos, screenshots |
| GIF | Graphics Interchange Format | Lossless, 256 colours | Yes (simple) | Simple animation |
| TIFF | Tagged Image File Format | Usually lossless | Yes (layers possible) | Print and archive |
| BMP | Bitmap | None | No | Legacy use |
Table 4. Common shared formats.
Cham tipChoose PNG for flat colours and sharp lines, and JPEG for photographs.
Cham taskSave a screenshot as both PNG and JPEG. Compare sharpness of the text.
Check yourself: Which of PNG and JPEG supports transparency?
PNG.
What are WebP, HEIF, HEIC and AVIF?
Short answer. These are modern formats that give smaller files than JPEG at similar quality. WebP is made for the web. HEIF and AVIF are newer image container formats.
- WebP is an image format developed by Google for the web. It supports lossy and lossless compression, transparency and animation, and it gives smaller files than JPEG or PNG in most cases.
- HEIF, High Efficiency Image File Format, is a container standard from the MPEG group. HEIC is the common file type that stores images compressed with HEVC. Many phones use it to save space.
- AVIF, AV1 Image File Format, stores images compressed with the AV1 codec and is also designed for the web.
- Not every program or website reads HEIC or AVIF yet. Export a JPEG or WebP when you must share widely.
- For your own website, WebP is a good default for photographs because the files are small and browsers read it.
| Format | Full form | Best for |
|---|---|---|
| WebP | Name has no official long form (Google) | Web photos and graphics |
| HEIF / HEIC | High Efficiency Image File Format | Phone photos, saving space |
| AVIF | AV1 Image File Format | Web, very small files |
Table 5. Modern compressed formats.
Cham tipUse WebP for website photos, but keep a JPEG or RAW master.
Cham taskConvert a JPEG photo to WebP at similar quality. Compare the file sizes.
Check yourself: Which format is made by Google for the web?
WebP.
What are the RAW formats in cinema cameras?
Short answer. Cinema makers use RAW video formats that record sensor data frame by frame for grading in post-production.
- REDCODE RAW (.R3D) is used by RED cameras.
- ARRIRAW is used by ARRI cameras for uncompressed recording.
- Blackmagic RAW (BRAW) is used by Blackmagic cameras.
- Apple ProRes RAW is a RAW video format from Apple, recorded by some cameras and external recorders.
- Sony cameras use X-OCN and RAW options on cinema bodies.
- These files are very large. Plan card, drive and backup space before you shoot. See the Memory Cards guide.
| Format | Maker | Note |
|---|---|---|
| REDCODE RAW (R3D) | RED | Compressed RAW |
| ARRIRAW | ARRI | Uncompressed RAW |
| Blackmagic RAW (BRAW) | Blackmagic Design | Compressed RAW |
| ProRes RAW | Apple | Used in recorders and cameras |
| X-OCN | Sony | Compressed RAW |
Table 6. Cinema RAW formats.
Cham tipAsk the post house which format they want before you shoot.
Cham taskFind the recording formats of one cinema camera and list their data rates.
Check yourself: Which cinema RAW format is made by Blackmagic?
Blackmagic RAW, BRAW.
Which format should you use?
Short answer. Shoot RAW for the master, keep a lossless copy for editing and export JPEG, PNG or WebP for delivery.
- Capture: RAW if you will edit, JPEG if you need speed and small files.
- Master and archive: keep the RAW, and a TIFF or DNG copy of important edited images.
- Print: TIFF or a high quality JPEG as the print shop asks.
- Web: WebP or JPEG for photographs, PNG for graphics with transparency.
- Always keep the original file.
| Job | Use |
|---|---|
| Capture for editing | RAW |
| Quick share | JPEG |
| Archive master | RAW plus TIFF or DNG |
| TIFF or high quality JPEG | |
| Website photo | WebP or JPEG |
| Logo with transparency | PNG |
Table 7. Choosing a format by job.
Cham tipDecide the format for each stage before the shoot.
Cham taskWrite your own format plan for capture, editing, print and web.
Check yourself: What should you keep as the master?
The original RAW file.
Questions beginners ask
What are the RAW formats of different camera makers?
Canon uses CR3 and earlier CR2 and CRW. Nikon uses NEF. Sony uses ARW. Fujifilm uses RAF. Olympus and OM System use ORF. Panasonic uses RW2. Pentax uses PEF or DNG. Leica often uses DNG.
What does DNG stand for?
Digital Negative, a RAW format made by Adobe to be a standard way to archive RAW images.
What is the difference between JPEG and JPG?
Nothing. They are the same format. JPG is the shorter extension.
What does PNG stand for?
Portable Network Graphics. It is lossless and supports transparency.
What is WebP?
WebP is an image format developed by Google for the web. It supports lossy and lossless compression, transparency and animation.
Which file format is best for photographers?
Shoot RAW for the master, keep a lossless copy for editing, and export JPEG or WebP for sharing.
References
- FileInfo (n.d.) What are RAW images and the different raw image file formats? fileinfo.com/help/raw_image_formats
- Library of Congress (2023) Camera Raw Formats (CAM_RAW), Sustainability of Digital Formats. www.loc.gov/preservation/digital/formats/fdd/fdd000241.shtml
How to cite this guide. Alex, A., & Joseph, A. (2026). Image file formats: A guide for photographers and cinematographers. Creative Hut Academy. https://creativehut.org/library/image-file-formats/
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