If the TM Extra plugin is firing the wp_handle_upload hook, Imsanity will automatically resize the images. I’ve not heard one way or another whether that is the case, but if the images end up in the Media Library, *usually* that means the uploader is triggering the standard WP hooks.
If it isn’t running wp_handle_upload, you can use our EWWW Image Optimizer plugin (also free), which has the ability to resize images in any folder along with an hourly scheduled optimization option to keep images in such folders under control!