"Squashed" thumbnails with EXIF rotation metadata

[Ezwen]

Description

(I originally submitted a bug for riot-web here: https://github.com/vector-im/riot-web/issues/10903)

Consider a picture with EXIF rotation metadata (eg. a photo taken with a phone that was not turned 90° on the side), such as:

When opened in an application that takes into account EXIF rotation metadata, we see this:

However when we upload this picture in Riot, the thumbnail shows this:

Steps to reproduce

• Take a picture with your phone and without rotating your phone on the side.
• Upload the picture in a matrix room using Riot-web : the thumbnail appears, and while the photo was rotated by taking into account the EXIF metadata, it appears "squashed".

Version information

• Homeserver: my own private homeserver

• Version: 1.3.1

• Install method: official docker image

• Platform: Debian 9

[richvdh]

I guess this is a bug in #5039.

[fbruetting]

For me, the thumbnail in riot-web has the correct framesize (upright image), but the image data inside that frame is landscape-oriented – and therefore heavily distorted.

When I then click on it, the frame gets rotated (so that both the frame and the image data are landscape – so that it doesn’t get stretched/squeezed anymore, but the orientation still is wrong. Instead, the image data should have been rotated – so that both the frame and the image are upright.