Does a nearly transparent pixel count?

Yes. Any alpha greater than zero counts as visible, including alpha 1. An entirely transparent image keeps its original canvas with null visible bounds.

When should I use shared sequence union?

Use it when frames share the same source canvas and must keep their relative positions. It applies one common crop and offset to every frame, including empty members; all-empty sequences keep the original canvas.

BROWSER-LOCAL · ALPHA BOUNDS

Trim transparent pixels

Crop empty PNG borders individually, or use one shared crop for an animation sequence. Keep original dimensions and crop offsets in JSON.

Alpha greater than zero counts as visible

Individual mode finds the smallest rectangle containing every pixel with nonzero alpha. Even alpha 1 counts. It crops only outside that rectangle and records its offset from the original canvas. An entirely transparent image keeps its original dimensions with null visible bounds.

Use a shared union to preserve frame placement

Shared sequence union requires every selected PNG to have the same source dimensions, including empty frames. It finds one rectangle covering all visible pixels and applies that identical crop to every frame. A mixed empty frame receives the same crop; an entirely empty sequence keeps the original canvas.

Different individual crops can change how an engine positions frames. A shared crop keeps the original relative placement, including intended movement. It does not infer pivots, frame timing or animation tags.

Keep the original offset when importing

The manifest records source indices, original canvas sizes, source rectangles and trim offsets using top-left pixel coordinates. Place a crop back at its recorded offset to restore its position on the original canvas. This generic sidecar is not an engine-native atlas resource.

Use the sprite sheet maker to assemble compatible cropped frames. Keep your animation timing and other sidecars separately.

Selection and export limits

Choose 1–32 static PNGs, up to 10 MiB each and 64 MiB combined. Animated PNGs are rejected. Geometry, retained output and conservative memory limits also apply. One invalid source fails the entire job; cancellation publishes no partial selection.

Download selection-ordered PNGs, JSON or a ZIP containing the complete result. The preview shows only the first output, at most 128 pixels per edge. Processing stays on this device. Browser conversion can round partial-alpha colors and discard hidden RGB or source metadata; trimming also intentionally discards pixels outside the crop.

Work through a single PNG with its original offset or a shared crop for an animation sequence.

? QUESTIONS

Does a nearly transparent pixel count?: Yes. Any alpha greater than zero counts as visible, including alpha 1. An entirely transparent image keeps its original canvas with null visible bounds.
When should I use shared sequence union?: Use it when frames share the same source canvas and must keep their relative positions. It applies one common crop and offset to every frame, including empty members; all-empty sequences keep the original canvas.