Image Converter

What is Image Converter?

Free bulk image converter. Convert JPG, PNG, WebP, GIF, BMP images to any format in one batch. Runs entirely in your browser — no upload, download as ZIP. Browser-based image tools — no upload to servers, all processing done locally. TekPulse's Image Converter is completely free — no signup, no ads in results, and no data stored on our servers.

How to Use Image Converter Online

1. Upload one or more images (up to 20 files, 25MB each)
2. Select the target format: JPG, PNG, WebP, or BMP
3. Adjust the quality slider for lossy formats (JPG, WebP)
4. Click "Convert All" — each file is converted in your browser using the Canvas API
5. Download individual converted images or all as a ZIP file

Image Converter Formula & Calculation

This tool batch-converts images by drawing each one onto a canvas and re-exporting it in the target format. JPEG and WebP outputs use the browser's lossy encoder controlled by the quality slider (10–100%), trading fine detail for smaller files. PNG re-encodes losslessly — identical pixels, just a different compressed container, which is why PNG output doesn't shrink no matter how 'quality' is set (the option is hidden for PNG for this reason). BMP is the only format this tool builds manually in JavaScript rather than delegating to the browser: it writes a raw, completely uncompressed 24-bit bitmap (a 54-byte header followed by row-by-row pixel bytes, padded to 4-byte boundaries, stored bottom-to-top as the BMP spec requires) — which is why BMP files are always far larger than any other format for the same image.

Key Factors That Affect Your Result

1. Format choice for transparency — PNG and WebP support an alpha (transparency) channel; JPEG and BMP do not — converting a transparent PNG to JPEG fills transparent areas with a solid background color, which is often an unwanted surprise.
2. Lossy vs. lossless — Converting FROM a lossy format (JPEG) TO another lossy format (WebP) compounds quality loss since you're re-quantizing already-quantized data; converting from PNG (lossless) to JPEG is "cleaner" in that sense, though still lossy itself.
3. Animated GIFs — This tool converts only the first frame of an animated GIF, since canvas-based conversion has no concept of animation — for animated output, a dedicated video/GIF converter with frame-by-frame handling is needed.
4. BMP's size cost — Because BMP is uncompressed, a 1920×1080 photo that's ~300KB as JPEG can balloon to 6MB+ as BMP — only useful for compatibility with specific legacy software that requires uncompressed bitmaps.

Why Use TekPulse Image Converter?