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Lizely

Image Filter Effects

Apply auditable grayscale, sepia, invert, warm, or cool effects locally with an adjustable intensity and preserved alpha.

Privacy: your files never leave your device. All processing happens locally in your browser.

How to use

  1. 1.Choose a JPG, PNG, or WebP up to 25 MiB and select the desired effect.
  2. 2.Set intensity from 0% for the original channels to 100% for the full transformation, then choose Apply filter.
  3. 3.Inspect the same-size PNG preview, confirm important colors and transparency, and download the result.

About Image Filter Effects

Image Filter Effects applies a small set of understandable color transformations to a local JPG, PNG, or WebP. Choose Grayscale, Sepia, Invert, Warm, Cool, or Original, set an intensity from zero to 100 percent, and create a PNG at the same width and height as the source. The page shows the selected effect, intensity, dimensions, file size, and a result preview before download. It is intended for quick visual treatments where a transparent method is more useful than a large collection of unexplained presets.

Grayscale uses the red, green, and blue weighting defined by the W3C Filter Effects specification: 0.2126, 0.7152, and 0.0722. Those coefficients make green contribute more than red and blue to the resulting channel value. Sepia uses the specification’s three-by-three color matrix. Invert replaces each channel with its complement at full strength. For these effects, a lower intensity linearly interpolates between the original channels and the full transformed channels before the final result is rounded and clamped to an 8-bit value.

The order of operations matters. The implementation does not round the full-strength target before applying a partial intensity. It calculates the matrix result as a floating-point value, blends that value with the source according to the selected percentage, then rounds once at the end. That matches the amount-based matrix construction more closely and avoids avoidable one-level channel drift at intermediate strengths. External golden cases cover primary colors, black, white, channel clamping, alpha preservation, and partial grayscale and invert strengths.

Warm and Cool are intentionally simpler creative shifts. Warm adds up to 30 red levels and 10 green levels while subtracting up to 20 blue levels. Cool subtracts up to 20 red levels, adds up to five green levels, and adds up to 30 blue levels. The same intensity interpolation applies. These names describe a visual direction, not a measured white-balance correction, Kelvin conversion, camera profile, chromatic adaptation, or color-temperature calculation. The page states that limitation so a creative preset is not mistaken for calibrated color science.

Original leaves RGB values unchanged and is useful for confirming the local decode/export path. All effects preserve each pixel’s alpha channel. Transparent pixels therefore stay transparent, even though their hidden RGB values may be transformed. The tool does not crop, resize, rotate, sharpen, blur, denoise, detect faces, isolate subjects, or choose a filter automatically. It exports PNG so the result can retain transparency and avoids an implicit JPEG-quality decision.

Images are limited to 25 MiB before decoding, 16 megapixels after decoding, and 12,000 pixels on either edge. Decoded pixel buffers are far larger than compressed files, so these limits protect browser memory and reduce long main-thread work. Processing starts only after Apply filter is selected. A zero-delay task lets the busy state render before the pixel loop begins. Replacing the file or settings invalidates any older export, and temporary Object URLs are released when no longer needed.

All work happens in the current browser tab. The source is decoded to an in-memory canvas, its RGBA buffer is transformed with the selected function, and a new PNG Blob is created locally. No source pixels, filter choices, or result files are posted to Lizely. A file that the browser cannot decode produces a clear error rather than a blank result. The source file remains unchanged, and the download name includes the chosen effect.

Filters can alter readability, skin tones, brand colors, and the meaning of scientific or documentary images. Review the full result rather than relying only on the preset name. A grayscale image does not automatically have good text contrast, a sepia treatment does not authenticate age, and warm or cool shifts are not correction profiles. For color-critical print, medical, scientific, archival, or professional photographic work, use a color-managed application with the required profiles and calibration. This tool is a fast, local, explicitly defined pixel transformer.

Methodology & sources

Grayscale, sepia, and invert follow the W3C Filter Effects channel transforms. The selected intensity interpolates from original channels to the unrounded full-effect target, then channels are rounded and clamped once. Warm and cool use explicitly disclosed product-defined channel shifts. Alpha is preserved and dimensions are unchanged.

Frequently asked questions

Does the filter remove transparency?
No. The RGB channels are transformed while each pixel’s existing alpha value is preserved. Use Add Background to PNG if you need an opaque result.
Are Warm and Cool measured color-temperature corrections?
No. They are disclosed creative RGB channel shifts. They do not calculate Kelvin values, camera white balance, ICC profiles, or chromatic adaptation.
Why does the output use PNG?
PNG preserves transparency and avoids making a hidden lossy-quality choice. Convert the reviewed output separately if another delivery format is required.

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