FPDF error: Alpha channel not supported

Many PNG files have an Alpha channel imbedded in the file. The process listed below removes that Alpha Channel from the PNG file.

1. Open the PNG file in a graphics program
2. Save as a JPG format and close the file
3. Reopen the new JPG file in the graphics program
4. Save as a PNG file again
5. Reattach the new PNG file to your Sales Category