🔧 TL3 Tools

What This Converter Does

This tool re-encodes an image into PNG, JPEG, WebP, GIF, or BMP using your browser's built-in canvas support. It shows the original file size next to the converted size so you can compare, and it offers a quality slider for the two lossy formats. Nothing is uploaded; the source is read from your device and the result downloads as converted.png, converted.jpg, converted.webp, converted.gif, or converted.bmp.

How the Browser Re-Encodes Your Image

The source image is drawn onto a canvas at its natural width and height, then the canvas is exported through the toBlob method with the chosen MIME type. JPEG and WebP accept a quality argument between 0.10 and 1.0, which the encoder uses to decide how much detail to discard. PNG, GIF, and BMP are lossless, so no quality value is passed to them; the export simply preserves the pixels.

Worked Example: A 12-Megapixel Photo in Five Formats

A 12-megapixel photo is about 4000 x 3000 pixels. As an uncompressed BMP it takes exactly 4000 x 3000 x 3 bytes, roughly 34.3 MB, because every pixel stores three raw bytes. The same photo as a JPEG at quality 85 typically lands between 4 and 6 MB, since the encoder drops high-frequency detail the eye barely notices. A lossless PNG of the same scene often runs 15 to 25 MB because photographic noise resists compression. WebP at comparable quality usually beats JPEG by a useful margin, and a GIF would be capped at 256 colors, making it a poor fit for a full-color photo. Exact sizes vary with the scene's detail.

Why Only JPEG and WebP Get a Quality Slider

The slider appears for formats that can trade fidelity for file size. JPEG and WebP are lossy: raising the quality keeps more detail at the cost of bytes, while lowering it shrinks the file and introduces visible artifacts. PNG, GIF, and BMP are lossless, so there is no quality knob to turn, and the slider is hidden for them because any compression decision would change the pixels.

What This Tool Does Not Do

It does not resize, crop, or rotate the image; the output keeps the exact dimensions of the input. It converts one file at a time rather than a batch. Converting a JPEG to PNG will not restore the detail the JPEG discarded, because that information no longer exists. Animated GIFs are flattened to their first frame, since the canvas reads only a still image.

Image Format Converter FAQ

Which format is best for photos on the web?

WebP usually offers the best quality-to-size balance and is supported by all modern browsers. JPEG remains the safe default when you need maximum compatibility.

Why is my BMP file so enormous?

BMP stores every pixel with no compression at all, three bytes per pixel. That is correct behavior for the format, and it is why BMP is rarely used for web delivery.

Will converting a JPEG to PNG improve quality?

No. The conversion preserves the pixels it is given, and the damage from the original JPEG compression is already baked in. The file may grow, but the image will not get sharper.

Why is there no quality control for PNG?

PNG is lossless, so every pixel is kept exactly as drawn. With nothing discarded, there is no quality setting to adjust.

Does the tool change the dimensions?

No. The canvas is sized to the image's natural width and height, so the output has the same dimensions as the input.

Is my image uploaded to a server?

No. Conversion happens entirely in your browser via the canvas API, and the result is written back to your device as a download.

Picking the Right Format for the Job

Choose WebP for modern web pages where size matters, JPEG for photo sharing and compatibility, PNG for graphics, logos, screenshots, and anything needing transparency, GIF only for simple animations or pixel art, and BMP when a legacy tool insists on it. When the size difference between two candidates is small, the lossless option is usually the safer choice.

Reading the Size Comparison Honestly

The two sizes next to the preview tell you whether the conversion is worth keeping. A large drop, such as a multi-megabyte BMP shrinking to a few hundred kilobytes as WebP, signals a clear win for sharing. A small drop, or a file that grows, is normal when moving from a compressed format to a lossless one. The comparison is the point of the tool, so let it guide your format choice rather than assuming the newest option is always better.

What the Quality Slider Actually Controls

The slider spans 10 to 100, and every step maps directly to the quality argument the encoder receives, from 0.10 to 1.0. At the low end the file is small but blocky artifacts appear around edges and fine detail. At the high end the file grows while staying close to the source. Since the control only appears for JPEG and WebP, the lossless formats never tempt you with a trade-off they cannot offer.

Converting Between Lossy Formats Twice

Every lossy re-encode discards a little more detail, so turning a JPEG into another JPEG at the same quality loses a second generation of data. The fix is to keep the original camera file or a PNG master and convert from that each time. WebP makes a good intermediate target because it preserves most of the visible detail at a smaller size, but for archiving, PNG remains the best balance of fidelity and size, since BMP reaches the same fidelity at an enormous byte count.

The Format Menu and the Preview

The dropdown lists the five outputs in order: PNG, JPEG, WebP, GIF, then BMP. Moving between them switches the quality control on or off, because only the two lossy choices need it. After a conversion the preview panel swaps the old image for the freshly encoded one, and the Download button saves precisely that preview, under the filename converted followed by the matching extension.

Proportions Stay Untouched

Because the output never changes the pixel dimensions, the preview keeps the exact proportions of your original file. Converting a landscape image produces a landscape result, and a square stays square, which matters when the image will be placed inside a fixed layout or beside text.