HTML inline images work extremely slow

I am working with zoomy plugin.

I am generating first data:image/png from canvas, second data:image/png from hidden canvas which is 50% greater开发者_开发百科 than first (drawing synchonized):

<a href="data:image/png..." class="zoom">
    <img src="data:image/png..." alt="image" />
</a>

But in this case zoom works extremely slow. I should send each data to server and then obtain them as png files from server? Can I avoid this obvious solution?