ThorstenvBW when holding 50 images for one entity som "filehandling" is required and i somehow look at Album management on my phone ...
flagging an image as primary of Albumcover is very useful in internal and external (webites / apps) listings showing always the most important image of all
sorting (a sortfield as number for example (1,2,3,4,5,100,200) could further draw on the same idiea but is more elaborate to incorporate (i guess) and to handle.
sorting on filename (camera's use order in filenames) is available already ?!
same for dates ?!
I think especially with a primary flag the image container would be much more useful (also to listings in Rei3) not only externally
(i did some "system tweaking") to accomplish those things : adding a leading 0 to the filename sorts that file as first in the gallery view, great but!! in a list form limiting the image container to 1 picture does not apply that sorting ... here order of import takes precedence ... a primary flag would fix this simpel en efficiently ?!)
Please have a look at how r3 manages files by creating your app and looking at the file data structures that you get when you run GET requests. There is some meta data available, that you can use for sorting - like the file name or change dates.
Cover images you can address, by using a separate files attribute.
For a cover image, it is also possible to use a different/fixed file name in the files list. This could be used by your endpoints that serve the files via CDN; although r3 internally would just treat it as a regular file. But I would need to get familiar with what you are planning to say anything more.
In general, r3 was not really built for such a scenario. It is primarily designed for internally accessed business apps, less for hosting large image galleries for public consumption. That does not mean that we cannot do it - but it might be necessary to add more features to r3 to enable such use cases. If you are planning to use r3 for your business, you can get in touch with us and we could discuss your requirements and how much effort new features would be to implement. Many organizations have sponsored features in r3 to fulfill new requirements - and still save money in the process.