No it is not wrong, although it is debatable. Your grasp of the difference between these is clearly poor.
Scandinavia has no official definition and is only a construct. Whether it includes Iceland is also debatable. Here are a whole bunch of images showing Finland as part of Scandinavia:
No mate, you are wrong. I don't care that you've googled a lot of pictures off some websites that think Finland is part of Scandinavia, it IS a definable area and Finland is NOT a part of it.
I won't waste time googling pictures, as the internet (and especially Wikipedia) is unreliable anyway.
Here is a nice example though: A poster from the 19th Century illustrating 'Scandinavianism'. Do you see a Finnish flag anywhere?
It is important to note, however, that Finland might ONCE have been considered a part of Scandinavia as it was under Swedish rule for many years. The same is true for Iceland which was under Danish rule.
But these two countries are now completely independent and are therefore no longer part of Scandinavia.
A similar (although not identical) example one could use, is Ireland. Ireland WAS considered part of the United Kingdom, but since its independence is no longer considered as such.
I hate to be a stubborn sour grape here, but I am a Dane, living in Denmark, and I know what I'm talking about.
Finland may have been considered part of Scandinavia ONCE, but only due to its being under Swedish rule.
It is a Nordic country, not a Scandinavian one.