The short answer
JPEG, sRGB, profile embedded, about 2048 px.
For anything you send or post, export JPEG in sRGB with the color profile embedded, at about 2048 pixels on the long edge. Keep full-size files for print and for your archive. Apple Photos can export this way; Preview's export sets only the format and quality. Graycard does it for a whole folder in one pass.
01Size
Bigger isn't better once a photo leaves your Mac. Instagram's Help Center says that when you share a photo, "we make sure to upload it at the best quality resolution possible (up to a width of 1080 pixels)." Messaging apps may also resize what you send. A 2048 px file is still wider than the 1080 pixels Instagram keeps, and much smaller than a full-size file.
| Where it goes | Export | Why |
|---|---|---|
| 2048 px, or 1080 px wide | Instagram uploads at up to 1080 pixels wide. Export 1080 wide if you'd rather do the downsizing yourself. | |
| Messages, WhatsApp | 2048 px | Enough for a phone screen. The app may resize it when it sends. |
| 1600 to 2048 px | Smaller files attach and download faster. | |
| A web gallery | 2560 px | Room for laptop and desktop screens. |
| Print, archive | Full size | A print needs every pixel. Keep the originals too. |
02Color profile: sRGB, embedded
A color profile tells the viewer how to read the numbers in a file. The web's color standard says that "untagged images must be treated as being in the sRGB color space", so sRGB is the one space that still reads correctly when a step along the way drops the profile or ignores it. Jeffrey Friedl's long-standing advice is the same: "When preparing a photo for web display, use sRGB", and "Embed color profiles in all images." Canon's manuals recommend sRGB for normal shooting.
| Profile | Use it for | If a step drops the profile |
|---|---|---|
| sRGB, embedded | Anything you send or post | Read as sRGB anyway, so nothing changes |
| Display P3, embedded | Apple devices and color-managed apps | Read as sRGB, so saturated colors look duller |
| Adobe RGB, embedded | Print work that asks for it | Read as sRGB, so colors look dull and muted |
| No profile | Nothing, if you can help it | Always read as sRGB, whatever the pixels were |
Friedl describes what a misread color space looks like: the result "can appear wrong", and usually "dull and muted". That is one cause of the washed-out look: a profile that didn't make the trip, or a viewer that ignored it.
03Adobe RGB or sRGB, in the camera
Many cameras let you set Adobe RGB for JPEGs. Canon's manual for the EOS R6 Mark II notes that "File names of still photos shot in the Adobe RGB color space begin with '_'", that "The ICC profile is not appended", and that "For normal shooting, sRGB is recommended."
Without a profile, the file says Adobe RGB only in its metadata. ExifTool's documentation explains that "an Adobe RGB image is indicated by 'Uncalibrated' with an InteropIndex of 'R03'." A viewer that reads profiles and not that tag treats the file as sRGB, and the colors come out dull.
Leave the camera on sRGB unless a print lab asks for Adobe RGB. If you already have Adobe RGB JPEGs, convert copies to sRGB with the profile embedded before you share them.
04Location
Photos can carry the place they were taken. Before you post publicly, decide whether that should travel with them. Graycard's For sharing preset removes GPS and location fields and keeps the shot date and camera; Full size and Print keep them. The Location row on the export sheet is Keep or Remove.
05JPEG quality
None of the places we checked publishes a JPEG quality to use, so this guide doesn't give a number. Graycard's default is fine for sharing; raise it for print if you like.
06Where to set it
| App | Where | What you choose |
|---|---|---|
| Apple Photos | File › Export › Export [number] Photos | Photo kind, JPEG quality, size, and color profile |
| Preview | File › Export Selected Images, with several images selected in the sidebar (File › Export for one image) | Format and, for JPEG, quality |
| Graycard | Export (⇧⌘E), then a preset | For sharing (2048 px, sRGB, GPS and location fields removed), Full size, or Print |
Graycard tags every JPEG sRGB or Display P3, keeps the shot date and camera, and has a Location row, Keep or Remove, for GPS and location fields. The For sharing preset sets all of it at once, for every photo in the folder, and Share sends the result to AirDrop, Messages, Mail, or Photos.
07Sources
Each source was opened and checked on October 8, 2026. Quotes are exact.
- Instagram Help Center, "Image resolution of photos you share on Instagram". help.instagram.com. Uploads at up to a width of 1080 pixels.
- W3C, "CSS Color Module Level 4", Candidate Recommendation Draft, October 7, 2026. w3.org. Untagged images are sRGB.
- Jeffrey Friedl, "Digital-Image Color Spaces, Page 7: Recommendations and Links", October 3, 2006. regex.info. Use sRGB for the web; embed profiles.
- Jeffrey Friedl, "Digital-Image Color Spaces, Page 2: Test Images", October 3, 2006. regex.info. A misread color space looks dull.
- Canon, EOS R6 Mark II manual, "Color Space". cam.start.canon. Adobe RGB file names, no ICC profile, sRGB recommended.
- ExifTool, "EXIF Tags", revised April 15, 2026. exiftool.org. Adobe RGB marked as Uncalibrated with InteropIndex R03.
- Apple Support, "Export photos, videos, slideshows, and memories on Mac". support.apple.com. Export options in Photos.
- Apple Support, "Convert image file types using Preview on Mac". support.apple.com. Export options in Preview.