I have a reference library section in the website. It is built by custom documents. Each library (i.e. Birds, Bears, etc.) has their own custom document. Right now I am at roughly 64,000 documents spread across 200 different custom documents. Everything is going great and now I have a new requirement.

I need to be able to allow regular authenticated site users (not editors) the ability to upload a photo or document. I need it attached to the document so it is in the documents life cycle (i.e. When document gets deleted so do all attachments). Here are the requirements.
1) Authenticated user can upload photo or document.
2) photo/document is stored with the custom document and within the document life cycle.
3) Users cannot modify or delete documents already uploaded. (Their own or others).
4) Display documents and photos/images to everyone.

I have mocked up using the contribution web part and that didn't meet all three criteria. I also attempted to use the file with direct uploader and that didn't work since it is 1 to 1. Then I tried the document attachments attribute type with a form control of Document attachments control, then using an alternative form just for that field. It came the closest, but the grid displayed allows editing of all attachments.

Perhaps I am over thinking it, but I just need a straightforward way for an end user authenticated, to simply be able to upload a document attachment, that I can resize to my specs during upload as well as limit the file type extensions. Once uploaded the users shouldn't be able to edit them again or delete them.

I was contemplating developing a custom control or web part, but I wanted to make sure that is the only way to go first.

Any thoughts would be very much appreciated.