Image Compression for Photographers

Wildly different things, and two of them will re-encode your file without telling you in the upload dialog.

Two details worth acting on. SmugMug converts HEIC on upload and does not keep the original: “We don’t retain a copy of the original HEIC file, so if you try to download the original at a later date, you’ll receive a high-quality JPEG instead.” If a phone is your second camera, convert HEIC yourself first. And CloudSpot is the only one of the five that accepts TIFF, which matters for 16-bit deliverables.

Pixieset publishes its download rungs, a useful check on what is worth uploading: “high-resolution (3600px or original resolution) or web size (640px, 1024px, or 2048px)”. If the client’s top tier is 3,600 px, a 6,000 px upload buys storage cost and nothing else.

Your copyright fields. This is where generic compression advice actively harms photographers: “strip metadata” is treated as an unambiguous good in every web-performance article ever written, and for a photographer it deletes the record of who made the picture.

The current IPTC Photo Metadata Standard is version 2025.1, revision 1, dated 26 November 2025. The fields that carry rights information, with their exact official names:

Version 2025.1 added four properties for AI-generated content: AI System Used, AI System Version Used, AI Prompt Information and AI Prompt Writer Name. Editorial clients will start asking about those.

Lightroom Classic gets this right, with options that are not obviously named. Adobe’s own export documentation lists four choices in the Metadata panel’s Include menu: Copyright Only, Copyright & Contact Info Only, All Except Camera Raw & Camera Info (everything except EXIF camera data such as Exposure, Focal Length and Date Time), and All.

The control worth knowing about is separate from that menu. Remove Location Info “removes GPS metadata from photos, even if All Except Camera Raw & Camera Info or All is chosen from the pop-up menu.” It is an override, not another toggle, which is exactly what you want: full IPTC rights data out, GPS coordinates of the client’s house gone, one checkbox.

Capture One exposes the same idea as removals in the Process Recipe. Its documentation names five: “Rating and Color Tag, Copyright, GPS Coordinates, Camera Metadata (EXIF), and All other metadata (IPTC)”, with everything except ratings and colour tags included by default.

One command tells you what actually came out, the same one we use in what EXIF data actually contains and removing EXIF data on Mac:

exiftool -G1 -a -s -Creator -Copyright -CopyrightNotice \
  -Credit -By-line -GPSPosition -SerialNumber export/*.jpg

Note how thoroughly the same information is duplicated: in one test file the photographer’s name appeared three times, as EXIF Artist, IPTC By-line and XMP dc:creator. Clearing one does not clear the others, which cuts both ways.

Often not, and the standards body that defines the fields has measured it. IPTC has run a recurring test on whether platforms preserve embedded metadata, in 2013, 2016 and Spring 2019. The 2016 round’s finding was blunt: “Ten sites removed at least some metadata when images were downloaded to a desktop environment” and “Only one social media site, Behance, received favorable results for retaining and displaying embedded data.”

Note the age. Spring 2019 is the most recent systematic study IPTC lists, so treat per-platform results as historical. The durable conclusion is structural: embedding your Copyright Notice is necessary and not sufficient, because you do not control the re-encoder at the other end.

One gallery vendor documents its behaviour, and only one. Zenfolio extracts IPTC on upload and states that “Unlike EXIF data, which is not supported by Zenfolio, IPTC is not recorded automatically by your camera”, listing five fields it recognises: Headline, Object Name, Caption, Keywords and Copyright notice. Pixieset, ShootProof, Pic-Time, SmugMug and CloudSpot say nothing about metadata in their file-requirement documentation; we checked, and the word does not appear.

The print copy should barely be compressed at all, and the labs say so themselves in language that surprises people.

Bay Photo’s file preparation guidelines are explicit: “We recommend that you DO NOT resize your files for ordering.” They publish no maximum file size. They constrain everything else: JPEG, TIFF or PNG with JPEG preferred, 8-bits per channel only (“16 or 32 bit files will become corrupted when imported into our systems”), RGB only, layers flattened, alpha channels removed, colour profile embedded, and “a resolution of 200-300 PPI at print size”.

WHCC gives the single most useful number in this whole article for anyone wondering how hard they can push JPEG for print: “We recommend saving your files at a JPEG quality of 10 or higher in Photoshop, 90% in Lightroom, or the equivalent in your editing tool.” They print most products at 300 DPI and resize submissions automatically, they accept P3 as well as Adobe RGB and sRGB, and engraving files need at least 1,200 PPI.

The stock row has hard numbers behind it. Adobe Stock requires JPEG in sRGB, a 4 MP minimum, 100 MP maximum and 45 MB maximum file size, and preserves titles and keywords added in Lightroom or Bridge. Shutterstock also sets a 4 MP floor, caps browser uploads at 50 MB, and converts everything to JPEG on approval. A 45 MB ceiling alongside “Don’t: Compress files too much” is a narrow target on a 60-megapixel file, and one of the few places a real file-size control beats a quality slider.

In the gaps, and the gaps are specific. Three of them come up repeatedly.

Formats your developer will not write. For a portfolio site you want AVIF or WebP, and at matched quality the difference is not small: on our Kodak test image, measured for the compressor roundup, 91,868 bytes of JPEG became 63,206 as WebP and 48,230 as AVIF. On a screenshot-style image the AVIF was 66% smaller while scoring higher on SSIM.

A hard file-size target. Lightroom’s export panel does offer Limit File Size To for JPEG, which Adobe documents as specifying “a maximum file size for the exported file”. Outside JPEG there is nothing. Smol’s neural encoder takes a targetKb between 4 and 4,096 for AVIF, WebP, JPEG or PNG. Asked for an AVIF under 100 KB from a 352,861-byte JPEG, it returned 51,140 bytes.

Mixed piles that are not a catalogue. The folder someone AirDropped you, phone HEICs from the second shooter, a contract PDF, forty screenshots for a tutorial. None of it belongs in a catalogue and all of it needs the same treatment.

The default you must change. Smol’s image defaults are quality 75, a 2,000 × 2,000 fit ceiling, and metadata stripping on. For a web asset that is correct. For your own work it deletes your Copyright Notice, Creator and Credit Line along with the camera serial. Turn it off before the first batch, and verify with the exiftool line above rather than trusting the setting.

One limit stated plainly: we read RAW, including CR2, NEF, ARW and DNG, and we do not develop it. No white balance, no highlight recovery, no lens profile. Pointed at untouched RAW you get a JPEG made from the camera’s own interpretation, which is not what you shot RAW for.

Four cases, and the first covers most professional delivery.

Your delivery runs through Lightroom or Capture One. Build an export preset and stop. It resizes, sets quality, chooses which metadata travels, and it is already open. An export preset is also reproducible in a way a drag-and-drop pass is not.

The files are going to a print lab. Bay Photo tells you not to resize. WHCC resizes for you at 300 DPI. Compression is the wrong instinct at the point where you are paying for ink.

You want provably lossless optimization. ImageOptim is free and the only tool in our roundup that produced pixel-identical output, verified at absolute error zero. On a 30-file batch it saved 5.8%, which is what honest lossless looks like.

You need RAW development, culling, or a catalogue. We are none of those things and will not become them.

Where a local app earns the $29: AVIF and WebP for your own site, a real byte target, phone and screenshot piles that never enter a catalogue, and a Finder right-click for the one-file-right-now case. Nothing is uploaded, which matters when the folder is a client’s wedding. Smol is $29 once. Adjacent guides: every method for compressing images on Mac and converting HEIC on Mac. For the privacy side of the same operation, see stripping GPS from photos.

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