Thumbnail Size/Shape Question

On my desktop computer, thumbnails seem to adjust to the shape of the document. They look more like a rectangle, including on the desktop. On my laptop, especially on the desktop, they are "squares." They are thumbnails, but documents look bad...a lot of white space on the sides. I have looked all over, used disk cleaner to delete cache(s), and nothing changes. Are thumbnails shape and size based on something else (e.g. monitor resolution...my desktop monitor is 1440p and the laptop is 1920 x 1200). Preference is all:)

Windows 11 does not have a direct slider for wallpaper sharpness, but you can maximize clarity by setting your display to its native resolution, using high-resolution images, and adjusting Windows' aggressive background compression via the Registry.

Fix Display and Image Settings

• • Native resolution: Right-click your desktop, select Display settings, and ensure your Display resolution is set to the (recommended) option.
  • Correct scaling: Keep the scale setting (e.g., 100% or 125%) on its recommended value.
  • Wallpaper fit: Go to Settings > Personalization > Background and set "Choose a fit for your desktop image" to Fill or Fit rather than Stretch.
  • Use native files: Use a source image that matches or exceeds your monitor's pixel dimensions (like 1920x1080 or 4K).

Increase Windows JPEG Quality Limit

By default, Windows heavily compresses JPEG wallpapers, making them look pixelated or fuzzy.

You can force Windows to display uncompressed images:

• • Press Win + R, type regedit, and hit Enter.
  • Navigate to HKEY_CURRENT_USER\Control Panel\Desktop.
  • Right-click an empty space, select New > DWORD (32-bit) Value, and name it JPEGImportQuality.
  • Double-click JPEGImportQuality, select Decimal, and type 100 as the value data.
  • Restart your PC and reapply your wallpaper.