Image Converter (PNG / JPG / WEBP)
Convert and resize images locally in your browser using the Canvas API. No uploads.
Loading Image Converter (PNG / JPG / WEBP)… If nothing happens, please enable JavaScript.
Frequently asked questions
Are my images uploaded to a server?
What formats can I convert between?
What is the difference between PNG, JPEG, and WebP?
Does converting JPEG to PNG improve quality?
What quality setting should I use for JPEG or WebP output?
What is the maximum file size the tool can handle?
How does browser-based conversion compare to server-side tools like ImageMagick?
Can I convert an image and resize it at the same time?
What happens to transparency when converting PNG to JPEG?
Is WebP widely supported by browsers?
About Image Converter (PNG / JPG / WEBP)
File conversion is the process of taking data stored in one format and re-encoding it in a different format while preserving as much of the original content as possible. For images, this means transforming the binary representation of pixel data from one codec's encoding scheme to another — for example, from the lossless per-channel compression used by PNG to the Discrete Cosine Transform used by JPEG, or to the modern prediction-based encoding used by WebP. Each format has different strengths: PNG preserves every pixel perfectly and supports transparent backgrounds, making it ideal for logos, icons, and screenshots; JPEG excels at compressing photographic images where slight quality loss is acceptable; WebP, introduced by Google in 2010, combines the best of both worlds with smaller file sizes and support for both lossy and lossless modes with an alpha channel.
The need to convert image formats arises constantly in real-world workflows. A graphic designer delivers assets as PNG but the CMS accepts only JPEG. A developer needs to convert a folder of JPEG product photos to WebP to comply with a performance requirement. A photographer exports HEIC images from an iPhone but the target platform does not support that format. A web developer needs to strip transparency from a PNG logo to create a JPEG thumbnail. Social media platforms, email clients, content management systems, and print services all impose their own format requirements, making image conversion one of the most frequent file-manipulation tasks across creative and technical professions.
This tool performs conversion entirely within your browser using the HTML Canvas API. The process works in three steps: the browser decodes the source image into raw RGBA pixel data in memory, the Canvas element renders those pixels, and then the Canvas's toBlob or toDataURL method re-encodes them in the target format at the quality level you specify. Because everything happens locally, your images are never transmitted to any server. There is no account, no file-size tier, and no watermark on the output. You can optionally resize the image during conversion, combining two common operations into a single step.
Client-side conversion has a few limitations worth understanding. The browser's built-in encoders are good but not as tunable as professional tools like ImageMagick, libvips, or FFmpeg. Very large images (above 20 megapixels) may hit the browser's canvas size limit or exhaust available memory. Converting from a lossless format like PNG to a lossy format like JPEG will introduce some quality loss that cannot be undone — always keep a copy of the original. Converting from JPEG to PNG does not recover the quality lost during the original JPEG encoding; the file will be larger but the detail that was discarded during the original JPEG save is gone permanently.
Formats, Codecs, and the Browser Wars: How Image Conversion Became Effortless
The history of image file formats is inseparable from the history of competing corporate interests and technical standards battles. When CompuServe introduced the GIF format in 1987, it was a deliberate act of generosity — the company wanted a way to share colour images over its online network and published the format openly. The mood soured in 1994 when Unisys revealed it held a patent on the LZW compression algorithm at the heart of GIF and began demanding royalties, triggering the creation of PNG as a patent-free replacement. JPEG, standardised in 1992, avoided similar controversy by being designed from the start as an open standard, though its core DCT algorithm had been patented in various forms — patents that quietly expired between 2006 and 2012. The JPEG format's longevity is extraordinary: despite being designed for the hardware capabilities of the early 1990s, it still accounts for roughly 70 % of all images on the web three decades later.
Browser vendors have historically used image format support as a competitive differentiator. Microsoft introduced PNG support in Internet Explorer 4 (1997) but had a notorious bug in its alpha-channel rendering that persisted for nearly a decade, forcing developers to use JavaScript workarounds for transparent PNGs. Google introduced WebP in 2010 and added native support to Chrome immediately, but Mozilla, Apple, and Microsoft initially declined to implement it, citing concerns about Google controlling the format. It took a decade of lobbying, performance data, and competitive pressure before all major browsers supported WebP. The same dynamic is playing out with AVIF (supported since Chrome 85 in 2020) and JPEG XL (whose Chrome support was added, then controversially removed in 2023, then restored).
The HTML Canvas API, which powers browser-based image conversion tools like this one, was first proposed by Apple in 2004 for use in the Safari browser and the macOS Dashboard widget system. It was subsequently adopted by all other browser vendors and standardised by the WHATWG. The Canvas specification's toBlob and toDataURL methods — the functions that re-encode pixel data into a specific image format — have been available in all major browsers since around 2012, quietly enabling an entire category of client-side image processing tools that would previously have required a server.