Convert to WebP, AVIF & more.

Which image format should you use?

The format you save an image in decides two things at once: how small the file is, and where it will open cleanly. There is no single winner — a photo, a logo with a transparent edge, and a text-heavy screenshot each have a different best answer. This tool converts between the four formats that cover almost every case, so the real question is which to pick and when.

The main formats, in plain terms

Four formats do nearly all the work on the modern web. Here is what each one is good at:

• JPG (JPEG) — the universal photo format. Lossy, small, and openable literally everywhere, but it has no transparency and shows blocky artefacts if you push the quality too low.
• PNG — lossless and sharp, with real transparency. Ideal for logos, icons, and screenshots with text; wasteful for photos, where the files balloon.
• WebP — the modern default. Roughly 25–35% smaller than JPG at the same visible quality, and it supports transparency too, so it replaces both JPG and PNG in most places.
• AVIF — the newest and smallest, often around half the size of JPG. Encoding is slower and a few older apps still choke on it, but for web delivery it is hard to beat.

Converting without a second quality loss

Lossy formats — JPG, WebP, and AVIF — throw away a little detail every time they are encoded. Convert an already-compressed JPG to WebP and you stack a second round of loss on the first, which is why a re-saved photo can look slightly softer than the original. Two habits avoid it. First, convert from the best source you have — the original or a lossless PNG master — not a file that has already been squeezed. Second, keep the quality slider high (90 or above) when you re-encode a photo; the file is still much smaller, and the second-generation loss stays invisible. PNG is the exception: it is lossless, so converting to or from it never degrades the image. If you only want a smaller file, not a new format, the compressor is the better tool — it trades quality for size on purpose.

When you actually need transparency

Transparency — a see-through background instead of a white box — exists only in PNG and WebP, never in JPG. Convert a transparent PNG to JPG and the empty areas fill with solid white, which is why a logo suddenly grows an ugly rectangle. So when an image has to sit on a coloured page or on top of another photo, keep it in PNG or WebP. If you are trying to create the transparency in the first place — cutting a subject out of its background — conversion won't do it; use the background remover to erase the backdrop, then export as PNG or WebP to keep the see-through edge. The transparent PNG guide walks through the whole process.

Old tools, new formats: compatibility

Newer formats save bytes, but only where they open. WebP is safe almost everywhere now — every current browser, most editors, every major platform. AVIF is close behind for browsers but still trips up some desktop apps and older content systems. JPG and PNG, by contrast, open in anything ever made. So the rule is simple: use WebP or AVIF for anything shown on the web, and convert back to JPG or PNG when a file has to go into an old editor, a strict upload form, or a print workflow that predates them. Because this tool goes both ways, that round trip is one click — pick JPG or PNG as the output and re-export. For the full comparison, see the PNG vs JPG guide; the what is AVIF guide covers where AVIF is worth it.

Converting a whole batch at once

You rarely convert just one image. Drop a whole folder, pick a single output format, and every file is re-encoded on your device and zipped into one download — the same quality setting across the batch. Nothing is uploaded; conversion runs in your browser with WebAssembly, so a hundred files stay as private as one. For a mixed folder, the "Keep" option leaves each file in its own format while still applying your quality setting.

Still deciding between the modern formats? Start with the PNG to WebP guide for the most common upgrade, then read WebP vs AVIF to see how much further AVIF can go.