are the folios marked by your own art teacher or by an examiner?
Again, this can vary from school to school, but generally the folios are marked by your classroom teacher. Occasionally VCAA will do an audit (selecting a couple of schools per year and remarking everything to make sure the teachers are assessing fairly.) If this happens, you should be told.
Even if you have an awful teacher and get audited, they'll realise something is up with the marking if the whole cohort's scores are wonky.
Cater to your teacher and you should by fine

are the folios marked by your own art teacher or by an examiner?
is it really such a bad idea to use 'second-hand' images (images from the internet, etc.) rather than taking your own? I'd heard it is, but I'm not sure that the website I read this on was catered for vce students- it was probably more of a uni student guide.
[/quote] Can't see why this would be a problem. Obviously if you were claiming other people's work was your own, then you might be in trouble, but in terms of research, I'd say it's almost required.
Your folio should follow some vague progression of brainstorming/ idea generation --> researching artists and artworks ---> developing purpose, message, and formal elements --> trialling --> documenting process --> discussing final decisions --> photos of final.
^Just my recommendations, this isn't set in stone or anything. But I'd imagine most teachers would be keen to have you look at artists you find interesting, or who have used similar materials and techniques.
Probably a good idea to combine this documentations with trials though - a page of research on Warhol's work, and then a few pages where you replicate or adapt his technique.
You could also go to art galleries and take your own photos of artworks, especially if there's a relevant exhibit being shown. This can earn you brownie points with your teacher too, but you didn't hear it from me
