I am sure it's a painting as when I looked in the back it had old nails holding the board on which had woodworm, then when I touched it it does feel like a painting.
It's only the backing paper showing as I took the painting out and did not put in back in the frame properly. The painting is complete
Need to see the back of the picture. The weave of the canvas, stretchers, nails holding the canvas etc. are all relevant, are you sure it is an oil painting as you say it had a wormy backboard and that's not usual for an oil on canvas. Have you looked at it under a loupe?
This is the back of a 19th century canvas, I can't really see the actual back of yours, canvas is a weave material. The front of your picture has a weave so the back should have too. If it's paper or card it's likely a print, unless someone stuck the canvas on to card, you need to look closely using a magnifying glass or loupe. The nails do look old however.