forumAttachments for bbPress (AKA: GD bbPress Attachments) is an easy-to-use plugin for WordPress and bbPress for implementing file upload for bbPress Forums topics and replies. You can control file sizes from the main plugin settings panel, or you can change some attachment settings for each forum individually. Currently, included features:

Attachments are handled through the WordPress media library.
Limit the number of files to upload at once.
Embed a list of attached files into topics and replies.
Attachment icon in the topic list for topics with attachments.
Attachments icons for file types in the attachment list.
Option to control if visitors can see a list of attachments.
Display uploaded images as thumbnails.
Control thumbnail size.
Control thumbnail CLASS and REL attributes.
Upload errors can be logged.
Post authors and administrators can see errors.
Tool to clean up uploads error log entries from postmeta table.
Administration: attachments count for topics and replies.
Administration: metabox for settings override for forums.
Administration: metabox with attachment list and errors for topics and replies.

bbPress Plugin Versions

forumAttachments for bbPress 5.0 supports bbPress 2.6.2 or newer. Older bbPress versions are no longer supported!

More free Dev4Press plugins for bbPress

forumManager for bbPress – quick and bulk forums and topics edit
membersDirectory for bbPress – add a new page with a list of all forum members
powerSearch for bbPress – add advanced search to the bbPress topics
topicPolls for bbPress – add polls to the bbPress topics
forumTools for bbPress – various expansion tools for forums

Upgrade to forumToolbox for bbPress

AKA: GD bbPress Toolbox Pro. The Pro version contains 63 features, with over 500 options to control the integration:

Enhanced attachments features
Attachments upload drop zone
Multiple files upload and validation
Limit file types attachments upload
Add custom file types for upload
BBCodes editor toolbar
Report topics and replies
Say thanks to forum members
Various SEO features
Various privacy features
Enable TinyMCE editor
Private topics and replies
Auto closing of inactive topics
Notification email control
Show user stats in topics and replies
Track new and unread topics
Mute Forums and Users
Great new responsive admin UI
Setup Wizard
Forum-based settings overrides
Edit: BuddyPress support
40 BBCodes (including Hide and Spoiler)
19 more Topics Views
9 additional widgets
Many great tweaks
And much, much more

With more features on the roadmap exclusively for a Pro version.

More information about forumToolbox for bbbPress
More Premium plugins with bbPress Plugins Club