Does WeTransfer compress your photos?

A client says the photos look soft. You know they were sharp when they left. Somewhere between your card and their screen something changed, and the transfer is the obvious suspect because it is the part you understand least. It is almost never the transfer. This is what it usually is, and how to check rather than guess.

What a transfer service does

A file transfer service is a courier, not a darkroom. It reads the bytes you hand it, stores them, and hands the same bytes to whoever opens the link. It has no reason to decode a JPEG, and decoding one costs it money in CPU it would rather not spend.

WeTransfer, Dropbox, Google Drive and Kepla File Transfer all behave this way for the file you upload. A checksum of the file you sent and the file that arrives will match. If it did not, every architect and lawyer using these services would have noticed long before photographers did.

The one thing that varies is the container. Some services zip a multi file transfer, some do not. Zipping is lossless: it repacks bytes without re-encoding pixels. A JPEG that comes out of a ZIP is byte for byte the JPEG that went in.

Where the quality goes

In rough order of how often it is the answer:

• The client put it on Instagram, WhatsApp or iMessage. All three re-encode aggressively. WhatsApp in particular resizes to a long edge measured in low thousands and re-compresses hard. The client then screenshots that and sends it to you asking why it looks bad.
• Google Photos with storage saver on. It re-encodes on upload by design. The original is gone unless they paid for original quality.
• Your own export settings. A quality slider at 60 with a 2048px long edge is a decision you made months ago and forgot. Check the preset before you blame anything downstream.
• The client is viewing a preview rather than the file. Mail apps, Slack and every gallery site show a generated thumbnail. It will look softer than the file sitting behind it. They may never have opened the image itself.
• Screenshotting. A screenshot of a photo on a 1080p laptop is a 1080p JPEG of a downscaled render. This is what most "it looks blurry" reports turn out to be.

Proving it in one command

Compare the files instead of arguing about it. On a Mac, open Terminal and run this against your original and the copy the client downloaded:

shasum -a 256 original.jpg downloaded.jpg

Two identical hashes means the file did not change in transit, full stop. Two different hashes means something re-encoded it, and now you know to look at what the file went through after it arrived.

A faster sanity check without a terminal: compare file sizes in Finder. A 14.2 MB export that arrives as 14.2 MB is the same file. A 14.2 MB export that comes back as 380 KB went through something.

Delivering so it cannot happen

You cannot stop a client putting your work through Instagram. You can remove every other variable:

• Send the full resolution file, in one archive. One ZIP of exactly what you exported, with nothing recompressed on the way. That is what Kepla File Transfer does: it packs the files as it uploads them, stores them as sent, and hands over the same bytes.
• Say what they are getting. One line in the message, "full resolution JPEGs, 14 MB each", pre-empts the whole conversation.
• Give them a social set separately. A folder of long edge 2048 files marked "for Instagram" means they use those instead of mangling the originals.

Do that and the next time someone says the photos look soft, you will know within a minute where to look.

FAQ