Use Latest Photo Option isn't Available When Attaching an Image (iOS)
There's no option to 'Use Last Photo' when I attach an image. Why not?
First, close the compose window and quit Twitterrific. Then look in Location services in your Settings app and make sure you give Twitterrific permission to use your location when tweeting. Twitterrific can't get proper access to your photo library without this. Once you give permission, this option should be available to you.
Also, keep in mind that this feature will work only with photos in your camera roll - albums, events, and movies won't work.