Topic 04 · Masks & selections

Delete a background, keep the sprite.

Downloaded art often sits on a flat colour. Select that colour, press Delete, and it's gone — the sprite drops onto transparency. Three clicks, no eraser.

A slime on a solid blue background — before — flat blue background

The same slime on transparency (checkerboard) — after — transparent

1Pick the colour picker for selections

Right panel → switch to the Mask tab. Use the Magic wand (two buttons: contiguous = connected pixels only, and + = the whole image) or Select same colour — both grab pixels by colour instead of by shape. For a background, the + whole-image wand catches it all at once; nudge the tol slider up a touch to forgive near-identical shades.

2Click the background

Click any empty background pixel. Every pixel of that colour joins the selection — you'll see the highlight fill the background and outline your sprite. Missed a patch (a shadow, a lighter edge)? Hold Shift (or set the mode to Add) and click it too — it stacks onto the selection.

The background selected — highlight around the whole canvas and the slime silhouette

3Delete it

Press Delete. The selected pixels clear to transparent — the checkerboard shows through. (Delete follows Aseprite: with a selection it clears just the selection; with none, it clears the whole cell.)

The background gone — slime on a transparency checkerboard

✓Cut out — export clean

Your sprite is now on transparency, ready to export as a PNG or pack into a sheet with no background to fight. Same trick works per-frame across a whole animation.

Halo? If a faint ring of old background colour clings to the edge, raise tol before deleting, or select the sprite instead and use mask → outer border to grab the one-pixel fringe, then Delete that.