Major update to the BB.

• Added: Submit buttons change after clicked
• Added: Oversized image handling (when not enough memory is available to generate a thumbnail)
• Added: Thumbnail caching
• Added: Reject image uploads based on pixel dimensions
• Added: Permanent post removal
• Modified: Post submission checks
• Modified: Thumbnail generation
• Modified: Minor cosmetic changes

Some of the criteria regarding accepted images have changed due to new features that enforce them, although for the most part it's still very forgiving. Please read this section for more information.