yeah, my cpu usage rose to above 80% without any running any additional code, though I couldn't say if it's a bitcoin miner as I am code-illiterate, for the most part.
It seems like it just scrolls through the page on a loop.
yes, I think the cause for the high cpu usage is a large, possibly uncompressed image file that takes a bit of processing to display in the browser, although other methods could be used to limit the processing or make the computation more efficient.