Photo file formats: what each is and what to do with it
The formats a family photo library holds, whether each one loses detail when saved, what the Library of Congress and the National Archives say about it, and this manual's advice: keep originals as they came and edit copies.
A file's format shows in its ending: .heic, .jpg, .png, .tif, .dng, or a camera maker's raw ending such as .nef, .cr3 or .arw. Lossy means the format throws away some detail each time the image is saved; lossless means it keeps every pixel exactly. The two archives' columns are written for institutions, not families; neither tells a household to convert its photos. Formats and the long term explains each row.
| Format | What makes it | Lossy or lossless | Library of Congress (photographs) | National Archives risk and plan | This manual's advice |
|---|---|---|---|---|---|
| HEIC (HEIF with HEVC compression) | iPhones and iPads since 2017, when Camera > Formats is High Efficiency | Lossy | Not listed | Moderate risk; if it opens easily, leave it as it is | Keep as it came. Make JPEG copies only to share. Change Camera > Formats only if a device in your home cannot open HEIC. |
| JPEG (.jpg) | Cameras and phones set to JPEG; iPhones set to Most Compatible; many shared and downloaded copies | Lossy | Preferred | Low risk; retain | Keep as it came. Opening, copying or captioning does not degrade it; saving an edit does, so edit a copy. |
| PNG | Some scans, exports and screenshots | Lossless | Preferred | Low risk; retain | Keep as it came. A lossless choice for scan masters if your software lacks TIFF. |
| TIFF (.tif) | Scanners; exports you choose | Lossless (uncompressed or lossless compression) | Preferred | Low risk; retain | The master format for scans. Make JPEG copies to share. |
| DNG | Some cameras and phones; Apple ProRAW is built on DNG 1.6 | Raw data, usually lossless | Acceptable | Low risk (DNG 1.6); retain | Keep as it came, beside any JPEG of the same shot. |
| Camera raw (.nef, .cr3, .arw and others) | Cameras set to save raw, often as a raw and JPEG pair | Raw sensor data; needs special software to view | Acceptable | Canon CR3 and Nikon NEF: moderate risk; NARA plans to transform them to DNG | Keep as it came, with its JPEG and the same name. Converting to DNG is a Go deeper choice in Formats and the long term. |
| Apple ProRAW | iPhones that offer ProRAW, when it is turned on | Raw data in a DNG file | Covered as DNG | No separate entry | Keep as it came. |
Sources
- Library of Congress, Recommended Formats Statement 2025-2026, still images: preferred and acceptable formats for photographs it collects; HEIC, WebP and AVIF are not listed. Written for published material the Library acquires, not for families.
- National Archives, Digital Preservation Framework (format action plans, release of 2026-10-21): the risk rating and planned action per format.
- Library of Congress format descriptions: HEIC, PNG, TIFF, DNG, camera raw, Apple ProRAW. The HEIC page was last updated in 2021, so its remarks about browsers and Windows codecs are dated.
- Library of Congress, The Signal (2013): a JPEG you will not modify can be archived as it is, with no benefit from converting it to TIFF.
- Apple, Using HEIF or HEVC media: the Camera Formats setting affects new photos only; sharing and USB import may convert to JPEG; Keep Originals stops that.
No one can say which formats will open in twenty years, and the archives' ratings describe risk for institutions holding millions of files. The table does not tell you to convert anything. The check that matters for a family library is the yearly one in Formats and the long term: open a sample of each format on the devices you use now.