Always set the size of your image ready for printing before you watermark the image. There are a few guidelines on image size to take note of:
The file size of the image to be watermarked must be less than 150 MB.
Your images must be larger than 600×300 pixels (or 300×600 pixels).
You can watermark any size of image up to the point where the combination of height x width (in pixels) is equal to 100,000,000 (examples: 10,000×10,000 pixels, or 50,000×2,000 pixels)