On a site of mine, my client is reporting that images that are reduced in size by code (i.e. specified a width/height) are appearing jagged and pixellated. I have asked her what browser she uses and inevitably it's Internet Explorer. 

Is there a way to optimise images in IE or do I need to manually resize the images on photoshop before I put them on the site?

The images in question are resized from 220x220 to 80x80 and I have javascript that expands them to 220x220 upon clicking.