ArtChanger (Paper 1.21.10) by bdiev_

Custom internet images in item frames with automatic grid sizing, high-quality rendering, persistence, and anti-dup protections.

Key Features

Load images from URLs (Instagram, Discord CDN, Telegram, Imgur, ImgBB, any direct link)
Auto grid sizing by aspect ratio (e.g., 1:1 → 3x3, 16:9 → 4x2, 4:3 → 4x3; manual 3x2 / 5x5 also supported)
Rectangular grids with placement validation and chunk-load restoration (tile metadata stored)
High-quality pipeline: multi-step downscale, sharpening, Floyd–Steinberg dithering, palette mapping to Minecraft maps
Rotate with right-click; delete with left-click (clears group, keeps main frame)
Anti-dup: auto-created frames do not drop; only one frame drops per grid
Persistence across restarts (image ID + grid metadata stored in frames)
Asynchronous downloads (non-blocking for the server)