Image format converter for JPG, PNG and WebP in one pass
Add several pictures on the left, pick a format and a quality, and the converted results stack up in the queue on the right. Each file shows its weight before and after along with the saving, so you can judge the result before saving. Your files never leave the browser.
Add pictures
Drop images here
JPG · PNG · WEBP · AVIF · BMP · several at once · up to 20MB each
Only formats this browser can actually encode are listed.
Converted queue
- Files
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- Source total
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- Converted total
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- Saving
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Showing a sample image. Add your own pictures and they take over right away.
Conversion happens inside your browser on a canvas. Files are never uploaded, and redrawing clears capture and location metadata. The quality value applies to lossy formats such as JPG and WebP and has no effect on PNG.
ready to use.
- Visible firstKeep the input and result positions clear.
- Results firstPut the main number up front and keep the process secondary.
- Less to askNo sign-up or extra information before using the tool.
How to use the image format converter
The same picture can differ several times over in weight depending on the format you save it as. Leaving a photograph as PNG makes it needlessly heavy, and turning a logo into JPG throws away its transparency. Format is a question of purpose, not preference.
This image format converter takes several pictures at once, turns them into JPG, PNG or WebP, and shows the weight before and after alongside the saving for each file. Only formats the browser can genuinely encode appear in the list, so you never receive a file whose name is the only thing that changed. Everything runs inside the browser.
Each format is good at something different
The three are not ranked against each other; they serve different content. Look at what the image contains and the answer follows.
- JPG — strong on photographs where colour varies continuously; no transparency
- PNG — for logos, icons and screenshots with hard edges, and for transparent backgrounds
- WebP — smaller than JPG at comparable quality and supports transparency; every major browser reads it
- A photograph left as PNG is usually several times larger than it needs to be
How this tool handles your files
When you pick files the browser paints each one on a canvas and writes it back out in the chosen format. There is no upload step, so it responds instantly and the originals are untouched.
- Changing format, quality or size reconverts the whole queue with no button to press
- The format list is built by testing which encoders the browser actually has
- Redrawing drops metadata such as capture and location information
Follow the screen in order
The left column holds input and settings, the right column holds the queue. One pass from top to bottom is enough.
- Drop several pictures on the left panel or press Choose files
- Pick the output format: JPG or WebP for photographs, PNG or WebP when you need transparency
- For a lossy format set the quality; around 80 is usually enough for photographs
- If you also need smaller pictures, set a ratio or exact pixels under Size
- Download files individually or save the whole queue as a ZIP
Where the quality value applies
Quality is the strength of lossy compression. The concept does not exist for a lossless format.
- JPG — the value applies directly; below 80 you start to see blotching at edges
- WebP — the value applies and yields a smaller file than JPG at the same setting
- PNG — lossless, so the result is identical whatever the value
- Re-compressing an already lossy file compounds the damage
Why only some formats are offered
A canvas can only write formats the browser has an encoder for. Ask for an unsupported one and it quietly returns PNG, so without checking you end up with a file whose name is the only thing that changed.
- On start this tool writes one tiny image in each format and reads back the type it received
- If the returned type differs from the requested one, that format is dropped from the list
- That is why the extension of every file you receive matches its actual contents
- If AVIF or BMP is missing, this browser simply has no encoder for it
When size has to come down too
Changing format alone often misses the target weight, and reducing width helps more than lowering quality.
- Scale by ratio — shrink everything by a percentage of the original
- Exact dimensions — enter the pixel target for width or height
- Leave aspect ratio locked and filling one side is enough
- Weight falls roughly with the square of the width
What to choose for which use
Knowing where the picture will sit settles both the format and the quality almost automatically.
- Blog body images — WebP at quality 80, around 1200px wide
- Product detail shots — JPG at quality 85 or above, original size
- Logos and icons — PNG or WebP, no resizing
- Email attachments — JPG at quality 70 to 75 to hit the size limit first
A worked example
Say you have ten 4032x3024 JPGs from a phone to publish on a blog.
- Add all ten at once and the source total appears above the queue
- Set the output format to WebP and the quality to 80
- Under Size choose scale by ratio and bring it down to around 30%
- Check the saving, then download everything as a ZIP
Common mistakes
Format conversion leaves losses you cannot undo. These four come up most.
- Turning a transparent PNG into JPG — the transparent area fills with white
- Converting JPG to PNG to save space — it usually grows several times instead
- Re-saving an already compressed JPG at low quality — the damage stacks
- Renaming the extension by hand — the contents stay the same, so the format does not change
Check before you save
Walking this list right before saving avoids a second pass.
- Are you exporting an image that needs transparency as JPG?
- Has the saving reached your target?
- Did you zoom into the most important picture to check quality?
- Do you still have the originals stored separately?
- Will the file names work where you intend to use them?
Frequently asked questions
Are my pictures uploaded to a server?
No. Every step from picking the files to saving happens inside the browser on your own device, so portraits and unreleased images are safe to work with here.
How many files can I add at once?
There is no fixed cap on the count. Each file can be up to 20MB, but adding dozens of large pictures uses a lot of browser memory, so working in batches is more reliable.
Why are AVIF and BMP missing from the list?
Because the browser has no encoder for them. Asking for an unsupported format makes the browser quietly return PNG, and saving that gives you a file whose contents are PNG under a different name. This tool tests each format once on start and lists only the ones that actually succeeded.
I converted to PNG and the file got bigger.
That is expected. PNG is lossless, so for photographs with complex colour it is far larger than JPG. To reduce the weight of a photograph choose JPG or WebP. PNG suits logos and screenshots where colour is simple and edges are hard.
Is transparency preserved?
Yes when exporting to PNG or WebP. JPG does not support transparency, so transparent areas fill with white. Do not convert logos that need transparency to JPG.
I lowered the quality but the PNG size did not change.
PNG is lossless, so the quality value does not apply. The on-screen quality affects only JPG and WebP. To reduce a PNG you have to change format or reduce the pixel dimensions.
Does converting cost quality?
Only when exporting to a lossy format. PNG is lossless so quality is preserved. That said, re-saving an already compressed JPG as JPG accumulates damage, so convert from the original in one pass where possible.
How is the saving calculated?
It is one hundred percent minus the converted weight divided by the source weight. A 1MB file becoming 300KB is roughly a 70% saving. A negative value means the result grew, which commonly happens when a photograph is converted to PNG.
How are the file names decided?
The original name is kept and only the extension changes to the new format. A ZIP uses the same naming, and a number is appended if two names collide.
References
Official documentation for canvas encoding and format support.