Twitter is rolling out a server-side update on its iOS and Android apps that will enable higher quality uploads from these platforms while also changing how the image appear on the timeline.
Both apps now support uploading images in 4K. This likely refers to the same 4096×4096 resolution limit that exists when uploading from Twitter web. Previously, the limit was 2K or 2048×2048 pixels.
Have a collection of higher res photos waiting to be shared? We’re testing ways for you to upload and view 4K images on Android and iOS.
If you're in the test, update your high-quality image preferences in “Data usage” settings to get started. pic.twitter.com/EgW5fsb8Z8
— Twitter Support (@TwitterSupport) March 10, 2021
To enable uploading in higher resolution, you will need to go into Settings and privacy > Data usage > High-quality images uploads and set it to either Mobile data & Wi-Fi or Wi-Fi only from the default Never. This will cause the app to compress the image less before uploading, which will increase the final resolution of the image but will also increase the upload file size and time it takes to upload the file.
To check the new feature, I uploaded a 4096×4096 image twice from the iOS app with and without 4K quality enabled and once through Twitter web. The non-4K mode compressed the file size and also changed the resolution to 2K.
The 4K mode reduced the file size by compressing it but the 4K resolution was maintained. Twitter web was the best, as it maintained both the resolution and file size (since the file was under the max 5MB that the site supports before it gets compressed) and thereby provided a lossless upload.
Most phone camera images far exceed these resolution limits, so they won’t be uploaded in lossless quality but you can still see them in much higher resolution now once they get uploaded than before.
Twitter also changed how images appear on your timeline. The default preview was always landscape regardless of what the image orientation was and Twitter used machine learning algorithms to generate an appropriate preview image that placed the subject in the window. Now, the app will simply show the full image on the timeline. There could be some limit to just how tall the images appear on the timeline but this feature wasn’t yet rolled out to me so I couldn’t check at the time of writing.
Unfortunately, it seems the company is still doing very little to improve the abysmal video quality on the app, which currently tops out at 720p and uses extremely aggressive compression. Of course, video is much more demanding on data and a switch to better quality may not be easy, at least not without switching to a more efficient codec like AV1 or VVC in future.