There are a few issues that can cause images to disppear in the final quote/invoice produced using the template system.
1. Make sure all images are set as "In line with text". Do this by right clicking on the image, and under wrap text. This will take away your ability to move the image around your document as easily, but produces the image correctly. If you need to move the image, use margins and tables.
2. Make sure to insert your logo/image into the document at full size, ie. Don't shrink the image after inserting into your document. If the image is too large for your document, shrink it using a photo editing package before inserting it into your document