User permissions for images and posts

Hi there, apologies if this is a topic that has already been explored, however I’ve looked at some of the most recent posts and there doesn’t seem to be something immediately relevant.

I’ve currently got a wordpress site running about 50 users who can all contribute. However, I want people to be able to upload their own images, when I use the ‘Role Management’ section, the only option that seems to be available is ‘Upload Files’. On selecting this option, the user then gets full access to the all the files and is able to delete exisiting content. What I basically need is the option for users to upload images as part of their posts and for them to be able to only have access to their own images.

This goes for the posts as well, there are posts on here that need to be edited or classed as spam, I do not want contributors to see these posts when they log in to contribute.

I’d really appreciate it if anyone has any ideas on how I can sort this out.

Thanks in advance,
Ash