Balanced or Lossless PNG: choose for the image

Smart PNG is the automatic starting point

The compressor now starts with Smart PNG, which tries adaptive color reduction and checks detail before choosing a smaller PNG. It keeps the file format. This can provide a more useful starting point than applying one fixed palette to every image.

Balanced and Lossless remain separate Manual choices. Use Balanced for more conservative color changes, or Lossless when decoded-pixel preservation at the original dimensions is required. Keep a source master and review the delivery image, whichever approach you choose.

Separate pixel preservation from the file container

A PNG file stores pixel data and may include other information such as metadata. Rewriting the file can change its bytes without requiring an intentional visual change to the decoded pixels. However, choosing a color-reduction mode changes the pixel representation itself. Those two approaches solve different problems and should not be described as interchangeable.

In PikoZip, Lossless preserves decoded pixels when dimensions are unchanged. Resizing is a separate operation: even a lossless PNG encoder cannot preserve the original pixel grid after you intentionally ask for fewer pixels. If exact source dimensions and decoded pixels are requirements, leave the width unchanged as well as choosing Lossless.

What Balanced is intended to do

Balanced permits color reduction to find a lighter PNG delivery copy while preserving alpha transparency. Similar colors may be represented more compactly. This can help some screenshots and graphics, but the suitability depends on the image. A gentle gradient and a flat icon do not respond in the same way.

The word balanced describes a practical starting point, not a guarantee of invisible changes. Inspect soft shadows, faint borders, gradients and small lettering. Compare representative areas at the scale you expect people to see. If a subtle shift is unacceptable for the asset, switch to Lossless and judge the resulting size honestly.

A smaller palette is a stronger compromise

The Smaller PNG mode uses up to 256 colors. That can be useful for simple artwork with a restrained palette, but it can be a poor fit for detailed photography or smooth multicolor transitions. Reducing the available colors may introduce visible steps or alter small details. A smaller number of bytes is not automatically a better asset.

Keep the original design export separately. You may need a different delivery copy later for another background, size or display. A transparent edge that looks acceptable on white can reveal a fringe on a dark layout. The comparison preview helps, and the final placement provides another important check.

Transparency and appearance are related but distinct

Alpha describes how pixels blend with what is behind them. Preserving transparency does not mean every color or edge remains identical after color reduction or resizing. Look at semitransparent shadows and antialiased boundaries as well as fully transparent areas. Product cutouts and logos often depend on those partial pixels.

JPEG has no alpha channel. If you explicitly convert a transparent image to JPEG, PikoZip fills transparent areas with white. That can be useful for a destination requiring JPG, but it changes how the image behaves on a colored page. Keep PNG or another supported alpha-capable format when the design needs transparency.

Choose the PNG mode instead of chasing a quality number

The lossy quality control is used for JPEG, WebP and AVIF. PNG has its own mode controls. If you are keeping a PNG as PNG, changing a lossy quality number is not the appropriate way to request a different PNG result. Read the active settings summary and choose the mode that matches the asset.

The original may be retained when it is already smaller than a same-format, same-dimension result. That does not mean the tool should discard detail until it reaches an arbitrary saving. It means the existing file is already a useful output at those settings. A different format is a separate option if the destination permits it.

A focused review before delivery

Use one representative export to compare the modes, keeping dimensions constant so you know which change you are judging. Once you choose an acceptable result, review several images from the collection rather than assuming the first one represents every texture and edge. The right mode may differ between a logo and a photographic banner.

For color-critical work, retain the master and inspect the result in its real workflow. Newly encoded outputs generally remove source metadata; an original retained because it is smaller keeps its original metadata. File size, color handling and archival requirements deserve separate decisions rather than a single optimization checkbox.

• Keep the source export.
• Confirm unchanged dimensions when required.
• Check gradients, small text and alpha edges.
• Test on the intended background.
• Read actual output bytes before downloading.

Measured examples: four sources, four PNG modes

We processed four non-private PNG fixtures through the same worker functions and pinned codecs used by PikoZip. Dimensions stayed unchanged. The Node harness copies UPNG-decoded RGBA pixels into the encoder; browser decoding and timing can differ. Original files, outputs, hashes and the reproduction script are linked in our compression benchmark guide.

The table reports exact file bytes. Exact pixels means the decoded RGBA arrays matched in this harness; it does not establish archival metadata preservation. Smart, Balanced and Palette may change colors. Inspect the downloaded output instead of treating a saving percentage as a quality score.