title: Custom metadata tags on iOS
body: <p>There is a similar question few years ago was asked in this thread <a href="https://stackoverflow.com/questions/6567240/how-does-one-add-custom-metadata-tags-to-an-image-on-the-iphone">this thread</a>. Unfortunately no answer was given. I know how to read and write defined EXIF, TIFF, etc. tags on iOS (kCGImageProperty* tags). The problem is Apple for some reason ignored many useful meta tags which I need in my app. Is there any way to "register" missing tags using standard iOS libraries, such that adding them to dictionary would end up in the meta-header of an image? </p>