🔄 Image Converter

Convert a picture between PNG, JPEG, WebP, BMP and ICO — and turn an SVG into any of them — without uploading anything. The file is decoded by your browser into raw pixels, optionally resized, then re-encoded in the format you pick and offered back as a download. No copy ever reaches tukuk.org: there is no upload box to bypass, no “processing” step on a server, and nothing you have to take on trust. Open your network tab — after the page loads, converting produces zero requests.

What each format is actually for

PNG is lossless and carries real transparency (an alpha channel), which is why logos, screenshots, line art and anything containing text look sharp in it. It is a poor choice for photographs — a PNG photo is routinely three to eight times the size of the same photo saved as a JPEG, because PNG's compression model cannot exploit the small, smooth colour changes photographs are mostly made of.

JPEG is lossy: it throws away high-frequency detail most eyes barely notice in exchange for files five to twenty times smaller. It has no transparency at all — convert a logo with a transparent background to JPEG and the gaps fill with whatever colour you picked above (white is the usual default, and this page fills white automatically if you leave “keep transparency” on a format that cannot store it). Repeatedly re-saving the same JPEG compounds the loss — “generation loss” — so always keep the original file.

WebP gives roughly the same visual quality as JPEG for 25–35% fewer bytes, and unlike JPEG it supports transparency. Every current browser opens it; a few older programs and some email clients still will not, which is exactly why “convert to WebP” and “convert back to JPEG” are both worth having on hand.

BMP is Microsoft's uncompressed bitmap: enormous by modern standards, but the one format that essentially every image viewer, print shop and industrial program written in the last forty years can open without a codec question. It is offered here for exactly that reason — a guaranteed-openable copy — never to save space.

ICO is the container a website favicon lives in: one or more images packed into a single file behind a small directory. Modern browsers accept a PNG stored directly inside an ICO, which is what this page produces — one PNG entry at the size you asked for, the widely-supported modern subset of the format rather than the older 16/32/48-px BMP entries.

SVG is the odd one out: it is a list of drawing instructions (paths, curves, colours), not a grid of pixels, so it scales to any size without blurring. That is also why it cannot simply be “saved as” PNG without first deciding on a pixel size — which is exactly what the width and height boxes above are for.

How the conversion actually happens

Your browser's image decoder turns the file into a grid of raw RGBA pixels held in a <canvas>. Resizing resamples that grid with a high-quality filter (not nearest-neighbour), so halving an image is close to what a dedicated desktop editor would produce; upscaling beyond the original resolution cannot invent detail that was never there and will look soft, whatever a website promises. The pixels are then re-encoded by the browser's own PNG, JPEG or WebP encoder. The BMP and ICO byte layouts are written directly from the same canvas — no third-party library is involved, so there is nothing extra to download and no server ever sees the file.

Honest limits

Turning a photo or logo into a real, editable SVG is not offered, and most sites that claim it run an auto-tracing service that approximates shapes and often gets them visibly wrong — genuine vectorisation is a separate craft with its own judgement calls, not a codec swap. Animated files (GIF, animated WebP/APNG) are read as their first frame only, because a single canvas cannot hold a timeline. Metadata — EXIF, GPS tags, camera model, colour profiles — is dropped by the decode/re-encode cycle; that is usually a privacy win and occasionally a colour-management one, worth checking before printing a converted photo. 16-bit or CMYK sources fall back to whatever your browser decodes them as, typically 8-bit RGB.

Part of Everyday Tools. Just need a smaller file rather than a different format? The image compressor keeps the format and drops the bytes. Need the pictures in a printable document instead? Images to PDF also runs entirely on your device.