@fabiomsilva It sounds to me like you have created custom thumbnails and you want to use those INSTEAD of the original thumbnails. If that’s the case, I have done this using FooGallery by uploading a custom thumbnail image separately in the Media Library and then setting the Custom URL field of the thumbnail to point to the original image. ALSO in your FooGallery settings, set Thumbnail Link to Custom URL. Hope this helps!