I have found the answer for this question, we cam blame the mirror.
Throughout the day we look at ourselves on the mirror at least eight times, and what we see is our flipped image but even though the image we see is not true, it is what we perceive as normal. So, when we look our image on a photograph, it looks weird or not normal because it is not flipped.
It's all about our sense of perception. We like the other people's photographs better then ours because we don't see their reflected image on a mirror so we perceive their photos as normal.
This conclusion is based on experiment I did with 12 people. First asked them to look at mirror and then I asked then to look at the true mirror, at the end they were all amazed by the difference between the regular and the true mirror. And what is a true mirror? It's also known as a non-reversing mirror. It is a device made by connecting two regular mirrors at their edges at a 90 degree angle. It shows an image as seeing on a photograph.