What is the WP3 file format?
.wp3 files belong to the category of project files. WP3 file contents are projects generated using Microsoft Photo Story 3, a free application released for Windows XP. Photo Story was used for creating multimedia slideshow presentations, so .wp3 files can store embedded images, audio soundtracks, narration recordings, text captions, and Pan & Zoom motion effects. The dedicated software enabled the export of presentations from .wp3 files to the .WMV format for playback on any Windows Media Player-equipped device.
Internally, a .wp3 file is a Microsoft Cabinet archive - identifiable by the MSCF signature at the start of the file - containing a project XML descriptor alongside embedded JPEG photos, WAV or WMA audio, and effect parameters. The raw contents can be extracted with 7-Zip, though the project cannot be re-assembled or rendered without Photo Story 3 itself. .wp3 files cannot be directly played back; they must be opened and rendered in Photo Story 3.
Photo Story 3 was never updated for Windows Vista or later and is not officially supported on Windows 10 or 11. As a result, .wp3 files are considered obsolete and are encountered only sporadically today. Rendering an existing project requires Photo Story 3 running on a legacy Windows XP or Windows 7 system.
Security & safety
RISK: LOWWP3 is a CAB archive containing photos and audio; no executable content. No known malware uses this format.
Format details
in a nutshellFULL NAMEMicrosoft Photo Story 3 Project Fileaka Photo Story project, WP3 project file
DEVELOPERMicrosoft Corporationsince 2004 (Photo Story 3 released October 2004)
CATEGORYVideo Files
MIME TYPEapplication/octet-stream
TYPECAB-based project container (slideshow/video project)
MAGIC BYTES · FILE SIGNATURE
OFFSET
00010203
HEX
4D534346
ASCII
MSCF
WP3 is a CAB archive; standard CAB magic bytes at offset 0
Programs that open WP3 files
Windows2 apps
Photo Story 3
Free Open the WP3 file in Photo Story 3, then use File → Save Story to render to WMV. Warning: may not work on Windows 10/11 without legacy components.
7-Zip (for content extraction only)
Open-source Rename .wp3 to .cab, then open with 7-Zip to extract embedded photos and audio files.
Web1 app
Technical details
deep spec| Container format | Microsoft Cabinet (CAB) archive |
| Magic bytes | `MSCF` (4D 53 43 46) at offset 0 |
| Byte order | Little-endian |
| Internal compression | MS-ZIP (LZX or MSZIP within CAB) |
| Embedded photo formats | JPEG, BMP |
| Embedded audio formats | WAV, WMA (narration recordings and background music) |
| Project descriptor | XML file within the CAB defining slide order, captions, and effect parameters |
| Motion effects | Pan & Zoom (Ken Burns-style) parameters stored in the XML descriptor |
| Export output | WMV (Windows Media Video) via Photo Story 3 render engine |
| Typical size | 1 MB - 500 MB (photo and audio content dependent) |
| Archive integrity | Per-block checksums (standard CAB format) |
| Rendering requirement | Must be opened and rendered in Photo Story 3 - direct playback is not possible |
| Released | 2004 (Photo Story 3 released October 2004) |
| Latest version | N/A (Photo Story 3 is the final version; software discontinued) |
WP3 conversions
Community Q&A
asked by users
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Frequently asked questions
How do I open a WP3 file on Windows 10 or 11?
Photo Story 3 (the original tool) often does not run on Windows 10/11. Try installing it in XP compatibility mode. Alternatively, rename the file to .cab and open with 7-Zip to extract the photos, or use the online converter at convert.guru.
How do I convert WP3 to MP4 or WMV?
Use the online converter at convert.guru/wp3-converter, or install Photo Story 3 and render to WMV (File → Save Story), then convert WMV to MP4 with HandBrake.
Can I extract photos from a WP3 file?
Yes. Rename the file from .wp3 to .cab, then open it with 7-Zip or WinRAR to extract the embedded JPEGs.
Is Photo Story 3 still available?
Microsoft still hosts the installer at microsoft.com/download but the software is discontinued and no longer supported. It was designed for Windows XP.
What replaced Photo Story 3?
The Microsoft Photos app (built into Windows 10/11) includes a video editor. Windows Movie Maker was another replacement but was also discontinued in 2017.
References
1Microsoft Q&A - Photo Story 3 WP3/WMV issueslearn.microsoft.com
2ArchiveTeam Just Solve - Microsoft Photo Storyjustsolve.archiveteam.org
