Fix for filters not working on older posts
If you have issues with the filters not working on uploads in older posts like me, turn off the “Organize my uploads into month- and year- based folders” option under Settings->Media. Now the filters will work only for the new uploaded media and after. So make sure that you do this right after your wordpress installation if you plan to use the ImageFX plugin.
Warning: Invalid argument supplied for foreach() in wp-content\plugins\imagefx\imagefx.php on line 409
You may you come accross the error above, when you try to upload a non-image file.
To fix this issue, override the imagefx_filter function in your theme and add a return before the foreach if the $meta variable is empty on line 408
if(empty($meta)) return $meta;