From there; this is an incredible tool for creating sprite sheets or static pixel art for use in private servers.

https://www.piskelapp.com

Standard Sizes for art in ROTMG Servers:

All of these are changeable; but typically the standard for servers.

Items & Equipment

• 8×8 pixels - All weapons, armor, rings, abilities, consumables, and loot bags are typically designed within an 8×8 canvas.
• Note: While a 16×16 item can physically be rendered in a private server's code, the community heavily rejects them as they break the standard user interface (UI) and inventory box styling. (Your source would need the UI / Inventory reworked to better accommodate these larger sizes, still worth looking into.)

🧙 Characters & Skins

Character assets are drawn inside specific sprite sheet dimensions to account for walking and attacking animations.

• 8×8 pixels (Standard) - Used for default classes, basic pets, and standard character skins.
  • Sprite Sheet Dimensions: 56×24 pixels (7 frames total: 3 for walking/side actions, 2 for moving up, 2 for moving down).
• 16×16 pixels (Large/ST) - Used for Set Tier (ST) transformations, complex skins, and legendary/divine pets.
  • Sprite Sheet Dimensions: 112×48 pixels.

Enemies & Bosses

Enemies use a wider variety of bounding boxes depending on their tier and visual importance:

• 8×8 pixels - Minor minions, pirates, beach monsters, and low-level dungeon enemies.
• 16×16 pixels - Most mid-game dungeon bosses, Godlands gods (Medusa, Beholder, etc.), and event minions.
• 32×32 pixels - Major event bosses and endgame dungeon bosses (Oryx, Malus, Void Entity).
• Custom (e.g., 64×64 or larger) - Some private servers implement massive custom canvas sizes for giant screen-filling multi-phase bosses. (I would stay away from "too large" of enemies, personally, but do what you want)

🧱 Environment & Particles

• Ground Tiles: 8×8 pixels (scaled by the engine to fit the 3D-camera perspective).
• Projectiles/Shots: 8×8 pixels (often using only the inner 4×4 or 6×6 pixels to leave transparent buffer space).