HEICPix / HEIC for Slack
Sending HEIC photos in Slack
You dropped an iPhone photo into a Slack channel and got "this file type isn't supported." Convert it to JPG first — takes 30 seconds in your browser.
The short fix
Drop your HEIC file into HEICPix, pick JPG, then drag the downloaded JPG into Slack. Done.
Convert HEIC for Slack now →Why does Slack reject HEIC?
Slack's file preview pipeline doesn't handle Apple's HEIC format. The upload itself doesn't fail outright — but the preview won't render and recipients on Android, Windows or older browsers can't open the attachment.
Slack has been "considering HEIC support" since 2020. Until they ship it, the workaround is converting to JPG first — which is universal.
Why not upload to a converter site?
Work photos often contain sensitive context — internal whiteboards, client documents on screen, badge photos, NDA-covered things. Uploading them to a random "online converter" sends them to someone else's server, with no real guarantee about what happens next.
HEICPix converts in your browser — the file never leaves your device. Safer for work data.
Long-term fix: stop iPhone from saving HEIC
If you regularly share work photos via Slack, you can make your iPhone save new photos as JPG by default:
- Settings → Camera → Formats
- Tap "Most Compatible"
Doesn't fix HEICs you've already taken — those still need HEICPix.