There are three ways to get seamless photographs.
1. Use a large enough background.
2. Use a seamless backdrop.
3. Filling in the background.
I am going to discus filling in the background with a simple program like paint.
Step 1: Background
I start by creating a mottled background if you don’t have one you can make one by selecting, copying and pasting a photograph of anything.
That is how I created these mottled backgrounds, I selected a ½ inch square, copied and pasted then reselected a ½ inch square, copied and pasted until I created these background.