Full screen mode: big images in landscape orientation are always shown at original size

[resoli]

Describe the bug
When using the full screen widget, landscape images larger than screen size are always displayed zoomed at original size. Only a portion of the image is visible, with (not working) scrollbars at side.
Portrait images are correctly shown (if screen is landscape, width > height).

To Reproduce
Steps to reproduce the behavior:

1. Open a landscape image.
2. Click on 'full screen' widget (square icon in the three dots menu)
3. The fulll screen mode is activated, but the image is not correctly resized to fit the screen.

Expected behavior
The image should fit screen size, being fully visible in its correct aspect ratio.

Screenshots
Image out of fullscreen

Same image in fullscreen mode:

Desktop (please complete the following information):

• OS: every tried: Android, Linux Mint, Ubuntu, Windows
• Browser: every tried: Fennec on mobile, Firefox, Brave, Librewolf

** Nextcloud version: **
v34.0.3 but this issue appeared several major versions ago.

[resoli]

Just tried with lanscape aspect ratio 'more square' (4:3) than screen one (16:9). In that case full screen display is correct, fitting vertically with black bars at sides.

[resoli]

The test image P9120196.JPG is 3968x2232 (16:9 aspect ratio). I tried to crop it reducing slightly the horizontal size: 3870x2232 . For the cropped image fullscreen is ok.