WordPress creates a new image at a reduced size when I specify the dimensions I want it to display, so when I choose 300 x 230 it produces this file as the image source:

<http://example.com/myphoto-300x230.jpg>

from this full-size version:

<http://example.com/myphoto.jpg>

I'm using a plugin to expand the 300x230 on rollover. The expanded view is the 300x230 blown up, which is blurry. Is there a way to show the full-size version on rollover, so that it's myphoto-300x230.jpg by default but myphoto.jpg on rollover? Would I need to regex the filename to get rid of the numbers for the dimensions?