A PICT image which entirely disappears when you scale, stretch it or use the zoom feature is probably corrupt. This has only been reported with a PICT graphic which was created in another application and brought into ClarisWorks or ClarisImpact.
To remove the corruption, copy the image, paste it to the Scrapbook (a Desk Accessory in the Apple menu), then copy from the Scrapbook and paste back into ClarisWorks. Alternatively, you can copy the image to a Draw document, Save As PICT and Insert/Place the PICT file.