SpriteFix Documentation

Grid vs Row Output Layouts

Single Row: Lays every frame out horizontally in one strip. The default, and best for standard animation sheets.

Grid: Arranges frames into rows and columns using Output Grid Rows and Frames per Row. Use this for large frame counts that would make a single row too wide.Pro Feature

Frame Extraction Modes

Auto-Detect Islandsscans for "islands" of color surrounded by transparency and treats each one as a frame. Best for messy sheets where frames don't touch.

Warning: If a sword swing or VFX physically disconnects from the character with empty space between them, it may be detected as its own frame. If your frames touch, overlap, or share borders, switch to Strict Grid Slicing instead.Pro Feature

Normalize Frames & Bottom-Center Alignment

With Normalize Frames on, SpriteFix calculates the visible bounding box of every frame, trims empty transparent edges, and aligns each one to the bottom-center of your chosen Output Frame Size.

This guarantees a character's feet perfectly touch the floor in Unity or Godot with no manual pivot adjustments (a 2px safety margin prevents bleeding). This setting is locked on whenever Pack into Sprite Sheet is enabled, since the sheet needs uniform frame sizes. To disable it, you must first turn off Pack into Sprite Sheet.

Uploading Multiple Files

Smart Auto-Detection: When you upload multiple files, SpriteFix analyzes the filenames and dimensions to determine if they are frames in a sequence, or completely independent sprite sheets, and configures the engine automatically.

Advanced Override: If you need manual control, click the Advanced Override button to force the engine to treat the files as individual frames, or extract islands from all of them and merge them together.

Strict Grid SlicingPro Feature

Ignores transparency entirely and slices the source sheet into equal-sized cells based on Input Grid Rows. Use this when frames touch, overlap, or share borders so Auto-Detect can't separate them.

Input Grid Rows must match how your source sheet is actually laid out — set it incorrectly and frames will be cut at the wrong boundaries.

Sprite Sheet, ZIP & Metadata Export

Pack into Sprite Sheet (on by default): combines every frame into a single PNG.

Off (Pro only): instead download a ZIP containing each processed frame as its own PNG.

Engine Metadata (Pro only): Enables generating Hitboxes & Anchors into a `.json` file. Note that enabling this will always output a ZIP archive so the metadata can be bundled.Pro Feature

Output Frame Size & Frame Count

Output Frame Size (16, 32, 64, 128, or 256px) is the pixel width and height of every frame in the final output. Pick a size large enough to fit your tallest/widest frame without clipping — larger sizes mean larger files.

Target Animation Frames (Single Row) or Frames per Row + Output Grid Rows (Grid) control how many frames appear in the final sheet and how they're arranged. To protect system memory, selecting a massive 256px frame size will dynamically limit your allowed frames to 8.

Animation Preview

After processing, the workspace shows a live, looping Animation Preview of your output sheet — for both Single Row and Grid layouts — so you can check frame order, alignment, and playback speed before downloading anything.

If something looks off (wrong order, blank frames, jumpy playback), use "← Adjust Settings & Reprocess" to fix it without starting over.

Adjust Settings & Reprocess

Don't like the result? On the Preview screen, click "← Adjust Settings & Reprocess" below the download buttons. SpriteFix takes you back to the Configure panel with your uploaded files and every setting exactly as you left them — change anything and click "Process Fixed Sprite" again.

You can repeat this as many times as you like. "Upload New Sprite" is still there in the header if you want to start over completely with different files.

Custom Outline Tool

Add a perfectly contoured solid stroke to every frame in your sprite sheet. You have full control over the Outline Color (via hex picker) and Thickness (up to 16px).

Excellent for making characters stand out against busy backgrounds or for instantly creating highlighted "selection" states without returning to your art program.

Troubleshooting Outputs

Is your frame too small? Make sure Output Frame Size is large enough to contain the tallest/widest frame in your sheet.

Are frames merging?Stray pixels or anti-aliasing fuzz can connect two frames under Auto-Detect Islands. Clean up your source art so there's 0 alpha transparency between frames, or switch to Strict Grid Slicing.

Outline clipping? If your custom outline looks cut off on the edges, your Output Frame Size is too small to fit the added thickness. Bump up the frame size to fix it!

Blurry sprites in your engine? Game engines like Unity and Godot default to bilinear filtering for 3D games. To fix pixel art blurriness, select your imported sprite sheet in the engine and change the Texture Filter mode to Point (No Filter) or Nearest Neighbor.

Browser freezing during processing? SpriteFix processes entirely in your local browser memory for privacy. If you select a massive 256px frame size and a large grid, it requires huge amounts of RAM. Try processing smaller batches or reducing the frame size.

Empty ZIP file or blocked download?Ensure your browser or ad-blocker isn't blocking local blob downloads. Also, if you use Auto-Detect on an entirely transparent image, it will extract 0 frames.