Hi,
It is a bit hard to answer, in some cases it might be possible. Generally multisite results pages are not capable of displaying results from across sites. There is a method in ajax search pro to basically force these results as ‘fake’ posts and change their URLs.
If you are somewhat familiar with theme coding, or already made changes to the theme files, then there is a theme function API available for the plugin. So if you can somehow locate the theme code where the images are printed, you could use this method (within the loop) to get the images parsed by Ajax Search Pro:
get_asp_result_field('image');
..this returns the result image, if available. I am honestly not sure if this would work with any multisite environment though.