If a person who was eating food and some drops of food on their clothes but when putting water on the clothes, it had become invisible and then this person performed salah in these clothes, but later on they discovered that the stains were still there - meaning when the water had dried out - the stain was there - does this person have to perform salah again?
Also, can a woman in her home perform salah in clothes that you can see the body through - but the body is covered is just you can see the skin colour etc
Food is not impure. Therefore if some food fell on one's clothes, the clothes will remain pure even if one did not wash them. If Salah is offered in the same clothes then the Salah will be valid.
A woman must cover her entire body except her face, feet and hands when she stands in prayer. If her body is covered with such a thin garment that her skin is revealed then her Salah will not be valid. She should cover her body with a garment that completely covers her body.
And Allah knows best.
Mufti Ikram ul Haq
Fatwa Center of America