Here’s a breakdown of the limits for files that are attached to a Chatter post or comment.
File Sharing Limits
A file can be shared a maximum of 100 times. This count includes shares with records, people, and groups. If a file is approaching the maximum, consider creating a public link or making the file public by posting it to your feed.
View the Shared With list on a file detail page to see who a file is shared with and their level of access.
File Size Limits
The file size limit for files that are attached to Chatter feed posts and comments is 2 GB.
File Privacy Limits
On private files, file metadata is not also private. A user without permission to access a private file can nonetheless access the file’s metadata. So, for example, through a private file’s metadata, an unpermitted user can see who’s following the private file. Salesforce doesn't remove geolocation information from uploaded images.
Folder Deletion
You can’t delete root folders from the org.