To add filters to a photo with adjustable intensity, open the Image Filter Effects tool, choose a JPG, PNG, or WebP up to 25 MiB, pick one of the six options (Grayscale, Sepia, Invert, Warm, Cool, or Original), set the strength from 0% to 100%, and select Apply filter. The processed image is generated in the same browser tab, the result is shown as a same-size PNG preview, and the download is built from the transformed pixels without ever sending the source file to a server. Intensity is applied as a linear blend between the original channel value and the fully transformed channel value, then rounded once at the end. That means a 50% setting gives fifty percent of the effect rather than a separate preset, and zero percent returns the original channels unchanged. Alpha is preserved on every pixel, so transparent regions stay transparent even when their hidden RGB values are transformed. The same workflow handles single-layer photos, layered PNGs, and strips of small banner images without any intermediate upload step.
Filters available and what each one does
The tool exposes six named options. Five are real filters and one is a passthrough. Each filter targets a different visual goal, and each one is defined by a documented pixel transformation rather than a hidden preset, so the result can be reasoned about before downloading. The Original option is the passthrough, leaves the RGB channels unchanged, and is useful for verifying the local decode and export path before committing to a specific look.
| Filter | What it does | Formula or channel shift | Best used for |
|---|---|---|---|
| Grayscale | Collapses RGB into a single luminance value | 0.2126·R + 0.7152·G + 0.0722·B (W3C) | Stripping color to focus on shape, contrast, or texture |
| Sepia | Tones the grayscale result with a brownish matrix | W3C 3×3 color matrix | Vintage or printed-page styling |
| Invert | Replaces each channel with its complement | 255 − channel | Negative film look, printable templates, masking helpers |
| Warm | Adds red and green, subtracts blue | +30 R, +10 G, −20 B at full strength | Golden-hour mood, food or landscape emphasis |
| Cool | Subtracts red, adds green and blue | −20 R, +5 G, +30 B at full strength | Cooler, shadowed, or winter mood |
| Original | Leaves RGB unchanged | n/a | Confirming the local decode and export path |
The W3C coefficients matter because green is weighted more heavily than red, and red is weighted more heavily than blue. A pixel with R=80, G=180, B=200 will produce a brighter grayscale value than a pixel with the same average brightness but a redder color balance, which is why foliage looks lighter than brick in monochrome photography. The same weighting feeds the sepia transform, which uses the W3C color matrix to push the grayscale result toward a warm brown rather than a neutral gray.
How to add a filter to a photo
The interface is built around a single preview, a filter selector, and a strength slider, so the steps are short and easy to repeat when processing a batch of images one at a time. The same steps apply whether the source is a JPG photo, a transparent PNG logo, or a WebP export.
- Open the Image Filter Effects tool in your browser.
- Choose a JPG, PNG, or WebP up to 25 MiB, then pick the desired effect from the dropdown.
- Set intensity from 0% (original channels) to 100% (full transformation) using the slider or numeric input.
- Select Apply filter. The page shows a busy state, then renders the same-size PNG preview.
- Inspect the preview, confirm important colors and transparency, then download the result.
How intensity actually changes each pixel
The intensity slider is not a preset picker. It linearly interpolates between the source pixel and the fully transformed pixel, then rounds once at the end. The W3C Filter Effects specification defines how grayscale, sepia, and invert are computed, and Image Filter Effects follows that definition with one explicit implementation choice: the full-strength target is kept as a floating-point value until the blend is complete, and only the final blended value is rounded and clamped to an 8-bit channel. Rounding once avoids the small one-level drift that appears when a target is rounded before it is blended with the source.
Worked example for grayscale on one pixel. Suppose an input pixel has R=100, G=150, B=200. The full-strength grayscale target is:
0.2126 × 100 + 0.7152 × 150 + 0.0722 × 200 = 21.26 + 107.28 + 14.44 = 142.98
At 50% intensity, the blended channel value is:
0.5 × 100 + 0.5 × 142.98 = 50 + 71.49 = 121.49
Rounded to the nearest 8-bit channel, the result is 121. The grayscale output ships the same luminance value on all three channels, so the final pixel is R=121, G=121, B=121 with the input pixel's alpha preserved. The full-strength coefficient table for grayscale is documented in the W3C Filter Effects specification, and the same blend rule applies to the sepia, invert, warm, and cool targets.
For Warm and Cool, the page discloses the exact channel shifts at full strength. Warm adds up to 30 levels of red, up to 10 levels of green, and subtracts up to 20 levels of blue. Cool subtracts up to 20 levels of red, adds up to 5 levels of green, and adds up to 30 levels of blue. At 50% intensity, Warm adds 15 red, 5 green, and subtracts 10 blue on top of the original channel values, after which the result is rounded and clamped to an 8-bit channel. That makes a 50% intensity reliably half the maximum shift rather than a separate creative preset, and the same float-blend-then-round rule applies.
Inputs, outputs, and limits that affect the task
Before opening a file, it helps to know the numbers that change whether the tool can complete the job. The page enforces these limits up front so that oversize or out-of-format files are rejected with a clear message rather than a blank preview. The three pixel-level limits interact, and a comfortably sized source is one that fits all three at once.
| Limit | Value | Why it matters |
|---|---|---|
| Source formats | JPG, PNG, WebP | Other formats are not decoded by the browser pipeline |
| Max file size before decoding | 25 MiB | Larger files are rejected at the file picker |
| Max decoded pixels | 16 megapixels | Decoded buffers are far larger than compressed files |
| Max edge length | 12,000 pixels on either side | Protects browser memory on long edges |
| Output format | PNG, same width and height as the source | Preserves alpha and avoids an implicit JPEG-quality choice |
| Alpha handling | Preserved per pixel | Transparent pixels stay transparent in the download |
| Processing location | Current browser tab | The source file is never uploaded |
A 25 MiB JPEG can decode to well over 100 megapixels, so the 16-megapixel cap often matters more than the file-size cap. A 12,000-pixel edge limit catches long panorama strips that would otherwise exhaust memory. Replacing the file or settings after the first run invalidates any older export, so a clean preview is required for each new setting before a download is generated.
What stays the same when a filter runs
The filter only changes RGB channel values. It does not crop, resize, rotate, sharpen, blur, denoise, detect faces, or isolate subjects, and it does not auto-select a filter for you. The output PNG is the same width and height as the source, and each pixel's existing alpha value is preserved, so a transparent logo layered over a colored plate keeps the same silhouette through the transformation. Transparent pixels still have hidden RGB values that the filter will transform, but the alpha remains at zero, so the visible shape of the image does not change.
The work happens entirely 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 sent to Lizely. If the browser cannot decode the file, the page shows a clear error rather than a blank result. The source file on disk remains unchanged, and the download name includes the chosen effect so the output is easy to identify later. Replacing the file or the settings invalidates any older export, and temporary Object URLs are released when no longer needed to keep the browser tab tidy.
Filters that change meaning, not just pixels
Filters can alter readability, skin tones, brand colors, and the meaning of scientific or documentary images, so it is worth reviewing the full result rather than relying 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 calibrated color-temperature corrections. The page explicitly states that Warm and Cool are creative RGB channel shifts, not Kelvin conversions, camera profiles, chromatic adaptation, or color-temperature calculations, so a creative preset is not mistaken for calibrated color science. Calibrated color science depends on device profiles, viewing conditions, and intent that a browser-based creative shift cannot provide, and the boundary is called out so the tool is not mistaken for a calibration reference.
For color-critical print, medical, scientific, archival, or professional photographic work, use a color-managed application with the required profiles and calibration. For everyday visual treatments, a few related tools cover the most common follow-up tasks: if you need a strict black-and-white result with no creative warmth, the Black and White Photo Converter uses the same W3C channel matrix but is dedicated to a single fully desaturated output. If your only goal is to invert the colors of a single image, the standalone Invert Image Colors tool does that one job with the same alpha handling. If you plan to take a filtered result into a motion project, see how to fit an image in After Effects with custom filter effects for the next step in the pipeline.