Ignoring Small Embedded Previews in RAW Images

RAW Previews

Sometimes older RAW files have embedded preview images with dimensions much smaller than the RAW file itself. For example, some early cameras included smallish 1200 pixel previews even if the RAW had 3500 or more pixels in each dimension.

The digital asset management system IMatch by default uses the embedded preview image to produce the thumbnails and cache images. That’s usually a lot faster than extracting and developing the full RAW data. But if the embedded preview is much smaller than the RAW image itself, this may lead to unwanted results and too small images in IMatch (Quick Preview, Viewer, Slide Show).

Modern cameras usually embed 100% previews, but older cameras did not. If your image archive managed by IMatch contains files produced by older cameras, you may run into this problem. But there is an easy solution.

Cache Settings

You can handle this situation easily with the cache preferences in IMatch. Go to Edit > Preferences > Cache to view and configure cache settings.

The trick is to tell IMatch to use the cache image in general (for speed) but only if the cache image dimensions exceed a certain pixel size. For example, if the too small cache images are 1200 or 1600 pixel, set the Minimal Size property to 2000 pixel:

The IMatch Cache Preferences for RAW previews

IMatch then uses embedded previews (from your new RAW files with standard 100% size previews) but falls back to developing the full RAW image if the embedded preview is less than 2000 pixel in either dimension. This gives you 100% previews for all your RAW files, old and new.

WIC Codecs

Sometimes the installed WIC Codec is unable to extract the embedded preview. In this case it usually helps to install the most recent WIC codec provided by your camera vendor, or a 3rd party WIC codec.

You can use the built-in WIC diagnosis in IMatch to check if the WIC codec installed on your system supports a given RAW image:

  • Select the file you want to check in a File Window
  • From the Help > Support menu, choose WIC Diagnosis

After a few seconds, IMatch displays a text file which lists all installed WIC codecs, the file extensions they support and the results for the selected file. This shows you if the WIC codec was able to extract a thumbnail, a preview and the full RAW image.

See also the knowledge base article WIC Support and Codec Availability for more information about WIC codecs.

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WIC Support and Codec Availability

What is IMatch?

IMatch is one of the leading Digital Asset Management Systems (DAM) for Windows.
Manage, catalog and organize all your RAW files, digital images, videos, audio recordings, PDF and Office documents etc. in one software.
See what IMatch can do for you.

What is WIC?

IMatch supports the Windows Imaging Component (WIC) framework supported in Windows 7, Windows 8, Windows 10 and later versions of Windows.

Windows WIC enables applications like IMatch to work with image formats (including RAW files) via so-called codecs provided by camera vendors, Microsoft or 3rd parties. Without the need to know the internal details of a file format, IMatch can handle the files as long as a working codec is installed.

Please ensure that you have always installed the latest RAW codec (WIC codec) available from your camera vendor’s web site (if your camera vendor supplies WIC codecs for your cameras). This ensures that IMatch can read and reproduce the images with the best possible quality. Camera vendors make changes to their RAW files almost with every camera model. If you work with scanners, microscopes and similar, your hardware vendor most likely also supplies a codec if the scanner emits a proprietary file format.

Note: Do not install multiple codecs from different vendors for the same RAW format. Experience tells that this may lead to more or less subtle problems when processing RAW files.

Windows Built-in WIC Codecs

Current Windows versions include a set of WIC codecs which support a wide range of common RAW formats. Note that not all camera format variants are supported, though.
Over the years, camera vendors introduced dozens of incompatible format variants which all use the same file extension. This complicates the process of providing a WIC codec for all camera models. Contact your camera vendor for assistance if you need more information.

HEIC/HEIF Support on Windows 10 and Windows 11

HEIC is a modern still image / video format mostly used on the Mac platform. In order to process HEIC files in IMatch you need to install a WIC codec. The standard WIC codecs included in Windows 10 don’t support HEIC/HEIF by default.

Microsoft provides a free WIC codec for Windows which adds support for HEIC to the operating system. To find this WIC codec, search for HEIF Image Extensions on the Microsoft web site or use your favorite search engine. Make sure you install the original codec created by Microsoft.

WIC Codec Download Sites

Note: Windows 11 includes a set of WIC codecs which support a wide variety of RAW formats. If your RAW format is not yet supported, contact your camera vendor and Microsoft for support.

Sadly, as far as we can determine, the only camera vendor who cares enough about their customers to provide an optimized WIC codec is Nikon.

See also this Wikipedia article for more information about WIC and the Microsoft  Windows Imaging Component Overview.

photools.com RAW Processing and LibRAW Support

If no WIC codec is available for one or more RAW variants you use, IMatch uses its built-in RAW processing pipeline based on LibRaw to create thumbnails and cache images.  LibRaw is an awesome OpenSource project which is actively maintained and supports hundreds of RAW format variants.

You can also switch to IMatch’s internal RAW processing when the default Windows WIC codec does not support the RAW variant your camera produces or if you experience problems like wrong orientation or similar.

They also offer an excellent and affordable software called FastRawViewer for viewing Raw files on the Mac and Windows.

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