Where is the image compression code?

[orazioedoardo]

I've noticed that signal-cli compresses image attachments like the official client, but I can't find the code that does this in the repo.

[AsamK]

No, signal-cli doesn't compress images.
When sending an attachment it uploads the file content as is.

[orazioedoardo]

Looks like it does, I've sent myself this picture from wikimedia, SHA1 afcc753d1b074975aa5910a8d409574e424f17da, 3869 × 1551 pixel. The received image is 3072 × 1231 pixel and obviously has a different checksum. Original metadata is also stripped. New metadata shows ProfileCopyright set to Google Inc. 2016.

[orazioedoardo]

Sorry to bother @AsamK, have you tried to reproduce this?

[exquo]

I think it's the signal servers that do the resizing and metadata stripping.

[orazioedoardo]

How would the server do that when the attachment is encrypted?

[exquo]

You're right, it should be encrypted on the device. I've been using too much Telegram lately, so had been thinking in that framework..
For reference, here's the signal-android's implementation: signalapp/Signal-Android#7542.