By default, Microsoft Windows does not support the proprietary file format of Adobe Photoshop ( .psd ). When a user navigates to a folder containing PSD files in Windows Explorer, the OS typically displays a generic icon (often the Photoshop feather logo) rather than the actual image contained within the file.
In the context of Windows, a "codec" (compressor-decompressor) usually refers to multimedia files. However, in this specific usage, it refers to a shell extension that allows the OS to generate and display thumbnails and previews for a file format it natively does not understand.
The most critical requirement for the Ardfry PSD Codec to function correctly is the setting in Adobe Photoshop.
Always download the codec from the official ARDFRY website or a trusted repository. After installation, you may need to restart Windows Explorer (or reboot) to see thumbnails appear.
Alternatively, users had to save a secondary .jpg or .png preview alongside the PSD, cluttering directories and doubling storage usage.