The Shift+Cmd+4 key combo is common from all the way back to Mac OS 9 (and maybe earlier?) to all Mac OS X and current MacOS versions and takes a screenshot of a selected area on the screen. On current MacOS versions the file saved to your desktop is in png format (Mac OS X versions around 10.4 saved screenshots in .tiff format), but on OS 9 it’s in a less common .pict format.
By today’s standards the .pict file format is even more unusual as it uses Classic Mac OS file system features called a ‘resource fork‘ and a ‘data fork’. The issue with copying these .pict files from a Classic Mac OS filesystem to a modern file system is described here – when you copy the file you get the ‘resource fork’ but lose the ‘data fork’, in this case losing most of the image file data. When I tried this and viewed or converted the file on MacOS each of the files only has a section of the image, or none at all.
To convert to a jpeg or other more commonly used format today, this post suggests using the Resize! app, which is still downloadable from kstudio.net.
The trouble with this approach is if you’ve already copied the .pict files from OS 9 to a SMB network drive, you’ve already lost part of the file and it won’t convert as expected.
The best option as described in the first post is to convert to a jpeg or gif on OS 9 before moving elsewhere. I’ve seen posts suggesting to use Quicktime Viewer, but the version I have on mg G4 running OS 9.2.2 doesn’t have a Save As or Export feature, not that I could find anyway.
Instead what I found that worked for me was to download GraphicsConverter from Mac Garden here and use Save As changing the file extension to .jpg
