It appears that the function of the two can be the same: A pinafore /ˈpɪnəfɔːr/ (colloquially a pinny /ˈpɪni/ in British English) is a sleeveless garment worn as an apron.[1] Pinafores may be worn by girls as a decorative garment and by both girls and women as a protective apron. A related term is pinafore dress (known as a jumper in American English), i.e. a sleeveless dress intended to be worn over a top or blouse. A key difference between a pinafore and a jumper dress is that the pinafore is open in the back. In informal British usage, however, a pinafore dress is sometimes referred to as simply a pinafore, which can lead to confusion. Nevertheless, this has led some authors to use the term "pinafore apron", although this is redundant as pinafore alone implies an apron. https://en.m.wikipedia.org/wiki/Pinafore# I would add that in American English, 'pinafore' is an obsolete term as far as I know. I've never heard the word used or seen one on a girl or a woman. I'm guessing that pinafores went obsolete in the second or third decade of the twentieth century in America. http://www.dictionary.com/browse/pinafore?s=t

No, they're very different! An apron is put over your regular clothes when you want to do a messy job such as cooking. Men and women can wear aprons. A pinafore is only for females, and it's a sleeveless dress which goes over a blouse or shirt. It is part of your regular clothes; not an addition. Have a look again at the images... by the way, you did the right thing by doing an image search first. :)

Where I come from in America "pinafore" is not used, but the shortened form "pinny" is. It is a item of clothing used by both sexes to keep clothes from getting dirty or damaged while painting, using a forge, gardening, doing pottery etc. An apron is what people use for the same purpose while cooking.

So to answer your question, no they aren't exactly the same. The pinafore can be an apron or a decorative garment.