I'm not sure why images don't show on your computer. Do you mean all images? The only ones in the article I mentioned are these:
Does your computer show those?
There are many different ways of painting your backcloth. But you don't have to paint one, you can always use a plain cloth, or a pattern. But one thing you do not do is try to paint on BLACK gauze.
The simple way is to have a black backcloth. Choose a lightweight velveteen or a dress velvet - hold it up in front to your face and see if you can see through it fairly clearly. If it isn't see through then you can't use it. I found a lovely dense black stretch dress velvet that was beautifully see-through.
Similarly you might find a striped material that would make a nice backcloth - hold it up to the light, or better get someone to help, and check that you can clearly see your hand through the cloth.
If you are going to paint it then you want to choose a white material, see-through, and preferably one that will not crease easily.
There are many different painting techniques with different fabric painting products on the market. You will have to experiment. There are fabric painting felt tip pens and paint in tubes and bottles. Some only work on man made fabrics, some only work with natural fabrics. The ones that dye the fabric rather than putting a textured layer on top of the fabric are the ones to choose. If you want to use acrylic paints then you mix thinly and stain the fabric rather than putting a layer of pigment on top. If you fill in the weave with pigment then you will not be able to see through.
Perhaps some people with more extensive experience with painting see through backings than I have will share their knowledge.