Hi Amy2012,
Welcome to Microsoft Community.
I understand your frustration with the "tiny oversized thumbnails" issue on your Windows 11 4K screen. As you mentioned, this issue has been asked before on the Microsoft Community Forums, and it affects many users like you, especially those who have invested in high-resolution monitors for tasks like photo editing.
The cause of this issue may lie in the way bitmap-based thumbnails are handled in Windows.
Bitmaps are pixel-based images and have a fixed resolution. When displayed on a high-resolution 4K screen, these bitmaps may appear smaller than expected, even if you select the "Extra Large" thumbnail view. This happens because bitmaps cannot be scaled without loss of quality, causing thumbnail issues. Improving this is really important for users who rely on high-resolution displays for photo editing and other visual tasks. While we cannot directly intervene in Microsoft's development process, providing feedback and drawing attention to this issue can help elevate their resolution priorities. Microsoft attaches great importance to user experience, you can submit your ideas and suggestions through the Feedback Hub, and the development team will regularly review submissions for ideas or fixes. Please share the feedback link here after submitting as it will allow others on the forum to vote for your submission, including me. More votes will lead to more visibility and higher priority to the development team.Remember to detail in your feedback how the issues are affecting your experience and work, and why improving thumbnail scaling on 4K screens is critical to you.While we do not have a specific timeline for addressing this issue, voicing your concerns through the appropriate channels can serve to draw attention to this matter and drive a resolution.
Thanks for your patience and understanding!
Best Regards,
Kyo - MSFT | Microsoft Community Support Specialist