Fancybox resizing images

Hi

I’ve installed the Fancybox WP plugin and it’s working great however whenever I upload a large image which might be 3000px wide it takes a really long time to load when the thumbnail is clicked on.

I was wondering if anyone knows of a way to automatically resize images for fancybox on upload rather than my client having to resize each image before uploading them.

Any help would be much appreciated.

Thanks.