Uploading retina screenshots are shown twice as large as they should be.

[ara4n]

Steps to reproduce

1. Take a smallish screenshot in macOS
2. Upload it as a PNG
3. Observe that the thumbnail is massive in the timeline - presumably the thumbnailing code has got confused by it being retina pixel density and is treating it as lo-dpi.
4. Instead it should be shown at the correct size.

For instance:

Outcome

What did you expect?

Image shown as a hi-dpi retina image, at the same physical size as it was on the screen (unless that can't fit in the timeline, when it should then shrink to scale)

What happened instead?

Image isn't recognised as retina, and is treated as lo-dpi.

To be precise, this code has regressed. Perhaps it's a browser/OS regression, and macOS 15.5 has changed the fingerprint we use to recognise screenshots as retina?

Operating system

macOS 15.5 (24F74)

Application version

Element Nightly version: 2025052204 Crypto version: Rust SDK 0.11.0 (f2e32d4), Vodozemac 0.9.0

How did you install the app?

nightly

Homeserver

matrix.org

Will you send logs?

No

[ara4n]

Looks like macOS is just no longer putting a pHYs chunk into its screenshots at all. In fact, i can't see a way to tell the right resolution, and macOS itself no longer shows screenshots at 1:1 resolution either :-/

[ara4n]

So this wonderful thread is a massive rabbithole of folks trying to understand the same misbehaviour: https://forum.keyboardmaestro.com/t/testing-on-why-the-click-at-found-image-action-fails/35855/19

TL;DR: If you take a screenshot to the clipboard with ⇧^⌘4 it works.

But if you save a screenshot to disk with ⇧⌘4 these days, for some people, it doesn't save resolution data for some reason.

I wonder if it's related to the fact I turned off the annoying preview after taking a screenshot, and the 'fast path' to disk mangles the metadata on the image.

[ara4n]

...yup, that's precisely what it is. If you have "Show floating thumbnail" enabled in the screenshot app it manages to save a PNG to disk with a pHYs block; if you don't, it doesn't (as of macOS 15.5, but I think it's been doing this for roughly a year).