APF Images
From Portal Puzzle Wiki
The following are the APF images we have discovered thus far. For access to raw dumps, look in the Dumps section.
They can be viewed online, with menu and images.
The name APERTURE is used by the Aperture Science Aperture Image Format File Viewer QBASIC program to denote the first file it should load upon starting. We do not yet have this file, though the image marked UNKNOWN below is currently serving as a placeholder for APERTURE until we do have it. We do not yet know the filename for UNKNOWN; however, it is unlikely that this is the first-file-in-the-set APERTURE file, as the intended purpose of this image appears to be a conclusion to the entire APF sequence.
[edit] Fake APF
The Aperture Menu/Picture Format can be trivially emulated by individuals attempting to fake leads. One such example is available here.
When decoded, the image looks like this: