I'm trying to determine whether this is a Steam issue, an MTG Arena issue, or an interaction between the two. On my system, screenshots taken with Steam's built-in screenshot function (F12) are saved at a much lower resolution than the resolution configured in MTG Arena.

Comparison with Native macOS Screenshots

When I use the standard macOS screenshot function (Shift + Command + 3), the screenshot is saved at the full rendered resolution. For example:

Case #1:
MTG Arena Resolution: 6144 × 3456
macOS screenshot: 6144 × 3456
Steam Screenshot (F12): 1536 × 864

Case #2:
MTG Arena Resolution: 5120 × 2880
macOS screenshot: 5120 × 2880
Steam Screenshot (F12): 2560 × 1440

This suggests that MTG Arena is rendering correctly and that the resolution reduction occurs somewhere during Steam's screenshot capture process. Additionally, I noticed that when the game is set to a 5K resolution, Steam screenshots are saved at exactly half the width and half the height of the configured resolution. However, when the game is set to a 6K resolution, the screenshots are saved at only one quarter of the width and height. This is particularly strange because the scaling factor is not consistent between 5K and 6K resolutions.

Questions

Has anyone else on macOS experienced similar behavior when using Steam screenshots with MTG Arena? I'd be interested to know whether this is specific to my setup or a more general issue affecting MTG Arena on macOS Retina displays.

System Information

Hardware: Mac Studio (2023)
Operating System: macOS Tahoe 26.5 (25F71)
MTG Arena Version: 2026.59.20 (4846.1277160)
Steam Version: 1779918128

Thanks in advance for any feedback.