The first challenge when making game sprites is inconsistent image sizes and backgrounds. When you generate characters separately with AI, sizes vary and backgrounds make them unusable in-game as-is. Sprite sheets require all characters to be placed in cells of identical size.
This post covers how to use XBRUSH's Outpainting and Background Removal features to standardize 8 different cat characters to 512×512 transparent PNG, then generate 4-frame attack sprite sheets using AI prompts.
- Generate characters — Create each character with separate AI prompts, establishing their costume, weapon, and class identity.
- Standardize size with Outpainting — Use XBRUSH Outpainting to expand each character's canvas to a consistent 512×512 square ratio.
- Remove backgrounds — Apply XBRUSH Background Removal to strip everything except the character, producing transparent PNG files.
- Write per-character prompts — Compose a 4-frame sprite sheet prompt for each character, specifying the animation sequence (Idle → Wind-up → Attack → Recovery) and fixed foot coordinates.
- Generate sprite sheets — Run the prompts to produce 2×2 grid sprite sheets. Regenerate variations as needed and select the best result.
Step 1: Standardize Character Size with Outpainting
When you generate 8 cat characters with different prompts, body proportions and on-screen sizes vary. For a sprite sheet, all characters must be represented at the same scale within the same canvas.
XBRUSH's Outpainting feature naturally extends the area around an image or stretches the canvas to a desired aspect ratio. Use it to add padding around cramped characters and match the canvas ratio to 1:1.
Adjust the expansion direction and size in Outpainting settings to match the canvas to a near-square 512×512 ratio. AI analyzes the existing image's background and style to naturally fill the new area.
Step 2: Apply Transparent Background with Background Removal
After standardizing size with Outpainting, use Background Removal to strip everything except the character. Game sprites need transparent backgrounds (PNG) to composite naturally with game engine backgrounds.
Background removal completes with a single button press. AI accurately recognizes character outlines, naturally separating even fur and equipment details.
Step 3: The 8 Completed Cat Characters
Results after Outpainting + Background Removal. All standardized to 512×512 transparent PNG.
Archer
Pirate
Barbarian
Priest
Mage
Paladin
Gladiator
Boxer
Step 4: Generate Sprite Sheets with AI Prompts
With characters ready, it's time to generate attack animation sprite sheets for each. Below are 4-frame sprite sheet prompts written for each character.
The format places 4 frames in a 2×2 grid — each frame following Idle → Wind-up → Attack → Recovery. Prompts specify fixed foot pixel coordinates to minimize sprite sheet wobble.
More frames means smoother animation. 4 frames is sufficient for quick creation, but writing prompts for 9 or 12 frames lets you express wind-up, impact, and afterimage in more detail. Also, changing equipment in the prompt directly changes the image — making it easy to create different sprite variants for the same character.
Archer Prompt
2D game sprite, pixel art/cartoon style, transparent background, consistent character design. 4-frame bow attack sprite sheet.
Side view cat archer facing right. 2x2 divided canvas, character centered in each cell, feet fixed at same pixel coordinates.
Frame 1 (Idle): Relaxed stance, bow loosely held at side, quiver on back, tail slightly curved.
Frame 2 (Draw): Bow raised, string pulled to cheek, body slightly turned, eyes focused on target, tail tense.
Frame 3 (Release): Arrow released, bowstring snapped forward, body leaned back, motion blur on arrow, tail whipped sharply.
Frame 4 (Recovery): Bow lowered to side, body returning to idle stance, tail settling softly.Pirate Prompt
2D game sprite, pixel art/cartoon style, transparent background, consistent character design. 4-frame sword attack sprite sheet.
Side view pirate cat facing right holding a cutlass. 2x2 divided canvas, character centered in each cell, feet fixed at same pixel coordinates.
Frame 1 (Idle): Relaxed stance, cutlass at side, pirate hat jauntily tilted, tail slightly curved.
Frame 2 (Wind-up): Cutlass pulled back overhead, body crouching, fierce grin, tail tensed upward.
Frame 3 (Attack): Powerful diagonal downward slash, motion blur on blade, body fully leaned into swing, tail swept forward.
Frame 4 (Recovery): Cutlass returned to defensive stance, body straightened, confident pose, tail lowered.Barbarian Prompt
2D game sprite, pixel art/cartoon style, transparent background, consistent character design. 4-frame claw attack.
Barbarian cat using massive claw weapons, side view facing right. 2x2 canvas, character centered in each cell, feet fixed at same pixel coordinates.
Frame 1 (Idle): Aggressive wide stance, both massive claws raised defensively, fierce expression, tail swinging.
Frame 2 (Wind-up): One claw pulled far back, body low and twisted, fierce growl, tail tensed and curled.
Frame 3 (Strike): Explosive forward punch, claw fully extended with motion blur and impact lines, body lunging, tail whipped forward violently.
Frame 4 (Recovery): Claws retracted, returning to aggressive defensive stance, tail swinging back in preparation for next attack.Priest Prompt
2D game sprite, pixel art/cartoon style, transparent background, consistent character design. 4-frame staff magic sprite sheet.
Side view priest cat facing right. 2x2 divided canvas, character centered in each cell, feet fixed at same pixel coordinates.
Frame 1 (Idle): Gentle stance, staff held upright with soft divine glow at tip, tail gently curved.
Frame 2 (Charge): Staff raised high, body leaning forward, glowing energy gathering at tip, eyes shining with divine light, tail rising.
Frame 3 (Cast): Climax — divine energy beam or orb launched forward, bright flash, body fully focused, tail fully raised.
Frame 4 (Recovery): Staff lowered, light fading softly, body returning to calm, peaceful expression, tail settling.Mage Prompt
2D game sprite, pixel art/cartoon style, transparent background, consistent character design. 4-frame magic staff sprite sheet.
Side view mage cat facing right. 2x2 divided canvas, character centered in each cell, feet fixed at same pixel coordinates.
Frame 1 (Idle): Confident stance, staff held diagonally, magic rune at tip faintly glowing, tail gently curved.
Frame 2 (Charge): Staff raised, magic energy swirling and sparkling at tip, body leaning into casting pose, eyes glowing purple, tail sharply raised.
Frame 3 (Release): Explosive magic energy blasted forward, tremendous magical discharge, body recoiling, sparks and runes scattering, tail swept.
Frame 4 (Recovery): Staff lowered, remaining sparks fading, body stabilized, satisfied expression, tail settling.Paladin Prompt
2D game sprite, pixel art/cartoon style, transparent background, consistent character design. 4-frame sword attack sprite sheet for paladin cat with sword and shield. Side view facing right. 2x2 divided canvas, character centered in each cell, feet fixed at same pixel coordinates.
Frame 1 (Idle): Calm stance, sword at side, shield relaxed, faint divine aura glowing, tail slightly curved.
Frame 2 (Wind-up): Sword pulled behind body, shield drawn tight, body twisted, eyes narrowed, tail tensed.
Frame 3 (Attack): Explosive horizontal slash, sword fully extended with motion blur, shield thrust forward for balance, holy light on blade, tail swept.
Frame 4 (Recovery): Sword returned to guard position, shield raised, body straightened, divine aura fading, tail settling.Gladiator Prompt
2D game sprite, pixel art/cartoon style, transparent background, consistent character design. 4-frame sword attack sprite sheet.
Side view gladiator cat facing right. 2x2 divided canvas, character centered in each cell, feet fixed at same pixel coordinates.
Frame 1 (Idle): Dignified stance, sword at side, tail gently curved.
Frame 2 (Wind-up): Body twisted back, sword pulled to hip in preparation for thrust, eyes narrowed, tail tensed.
Frame 3 (Strike): Explosive forward lunge, sword fully extended in powerful thrust, motion blur on blade, body pushed forward, tail swept.
Frame 4 (Recovery): Sword withdrawn, body returned to original stance, tail lowered.Boxer Prompt
2D game sprite, pixel art/cartoon style, transparent background, consistent character design. 4-frame knuckle attack with knuckles on both hands. Side view knuckle cat facing right. 2x2 divided canvas, character centered in each cell, feet fixed at same pixel coordinates.
Frame 1 (Idle): Classic boxing stance, knuckle fists raised firmly, feet spread athletic, tail curved.
Frame 2 (Wind-up): Weight shifted back, rear fist pulled back for cross punch preparation, front fist maintained high, eyes focused, tail tense.
Frame 3 (Strike): Powerful fully-extended cross knuckle punch, body rotated into punch, motion blur on fist, impact lines radiating from knuckles, tail swept.
Frame 4 (Recovery): Knuckle fists returned to guard, body back to boxing stance, light footwork expressed, tail settling.Want Smoother Animation? Try 9 or 12 Frames
4-frame sprites feel concise and retro, but for smoother animation, you can expand prompts to 9 or 12 frames.
9 frames: Idle(1) → Wind-up(2-3) → Attack prep(4) → Impact(5-6) → Afterimage(7) → Recovery(8-9)
12 frames: Adds foot movement, weight transfer, and post-attack hold to the 9-frame flow
More frames = more natural animation. Change the 2x2 grid to 3x3 or 3x4 in the prompt accordingly.
Change Equipment, Change the Sprite
Change helmet, armor, or weapon descriptions in the prompt and the image changes accordingly. For example, changing the Paladin's sword to a "flaming sword" and shield to a "dragon-crest shield" gives a completely different equipment set with the same character pose. Use this to efficiently create upgraded items, rare gear, and seasonal costume sprite variants.
Tools Used
XBRUSH Outpainting — Standardize character canvas to 512×512 square ratio
XBRUSH Background Removal — Remove background for transparent PNG sprite source
AI Prompts — Generate per-character 4-frame attack sprite sheets (expandable to 9·12 frames)
Related Posts
- 4-Frame vs 9-Frame Sprites — When Do You Need More Frames?
- How to Build Animation-Ready Character Part Sheets with AI
- The Solo Indie Dev's AI Art Workflow — Cut Production Time Without Cutting Quality
Frequently Asked Questions
Q: Why does XBRUSH Outpainting matter for sprite sheets, and can't I just crop or resize images manually?
Outpainting adds canvas space by generating new content that naturally matches the existing image's style and background — it doesn't just stretch pixels. For sprite sheets, this means you can adjust each character's framing and padding consistently without visual artifacts. Manual resizing would distort proportions, while outpainting preserves them.
Q: How do I keep all 8 characters visually consistent when generating them with separate prompts?
Start by defining a shared style in every prompt (e.g., "2D game character, cartoon style, side view facing right") and use the same core visual language across all prompts. XBRUSH also supports uploading a reference image so subsequent generations can match the established look. Generating all characters in the same session helps too.
Q: Can I use the resulting transparent PNG sprites directly in Unity or Godot?
Yes. The 512×512 transparent PNG files exported after Background Removal are directly importable into Unity, Godot, and most 2D game engines. Arrange them into a sprite sheet atlas using tools like TexturePacker, or import them individually and reference each frame in your animation controller.