Signal-desktop: [Data Usage] Compressing Drag&Drop/Clipboard Images Using JPEG instead of PNG

[Xashyar]

• [x] I have searched open and closed issues for duplicates
  

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Bug description

According to @jlund-signal Signal-Desktop compresses images using JPEG, but every time a photo is sent (drag&drop or screenshot) the sent image format is PNG, which often time is quite large (e.g. 2MB for a small screenshot).

https://community.signalusers.org/t/heif-webp-image-compression/

Platform info

Signal version: 1.18-Beta.7

Operating System: Windows 10

[Xashyar]

Related: #2923

[FxRe]

I'm not sure, if this should have its own issue: I'm using Signal for Android and the MacOS Desktop client. Sending pictures with Android, they are in HEIF, not JPEG. On Android they are being displayed correctly. The Desktop Client shows them as a generic file, meaning you have to download these pictures in order to be able to view them. If the Android (or any other) client is using HEIF and supports it fully, I think the Dekstop client should be able to handle them as well, because otherwise it's really inconvenient to use Signal on different platforms.

[Xashyar]

@FxRe

Neither Electron nor Chromium itself support HEIF yet.

https://www.electronjs.org/docs/api/native-image#supported-formats

Currently PNG and JPEG image formats are supported. PNG is recommended because of its support for transparency and lossless compression.

[FxRe]

Thanks, @Xashyar. I didn't even consider this, because for some reason I was sure that there was support for HEVC in Chromium, and subsequently also for HEIF. Thinking about how long HEVC is already out there and that it's probably not just a technical issue but also (maybe more importantly) patent/license/royalty foo that nobody wants do deal with, the lack of support isn't surprising.

In any case, I'm off topic here. This has nothing to do with the original issue, unless I'm missing something.