jpeg/png - JPEG PNG Converter
jpeg/png does one thing: it converts a single image between the two most common picture formats. Choose a JPEG and get a PNG, or choose a PNG and get a JPEG. There are no editing tools, filters or settings to learn, which makes it quick when a website, form or app accepts only one of the two formats.
Typical moments when you need it: an online application rejects your PNG scan and asks for a JPG, a design tool wants a PNG, or a screenshot is far too large to email and would be smaller as a JPEG. Instead of opening a full image editor, you pick the file, press one button and the converted copy is saved to your downloads.
The conversion happens entirely inside your browser using its built-in image engine. Your picture is not uploaded to any server, and the page works on phones and computers alike.
The app runs entirely in your browser. What you enter is saved only on this device.
How to use jpeg/png
- Select an image. Press Select image and choose a JPEG or PNG file from your device. A preview appears at the top; the X button clears it.
- Choose the target format. Press Convert to PNG to make a PNG, or Convert to JPG to make a JPEG. If the picture is already in that format, the app tells you and does nothing.
- Get the file. The converted image downloads straight away with the same name and the new extension, for example holiday.jpg becomes holiday.png.
- Download again if needed. The download icon in the top bar saves the last converted file once more, which helps if your browser blocked or misplaced the first download.
- Convert another picture. Press Change image to pick the next file. Each conversion is independent; nothing is kept after you leave the page.
Features
- JPEG to PNG and PNG to JPEG conversion
- Keeps the original pixel dimensions; the picture is not shrunk
- Transparent areas of a PNG become white in the JPEG instead of black
- Converted file downloads automatically with a matching file name
- Re-download button for the last result
- Warning when the picture is already in the chosen format
- Runs locally in the browser; no upload, no account
- Interface in many languages; add ?lang=en or ?lang=ja to choose
JPEG or PNG: which format should you use?
How the two formats store a picture
JPEG uses lossy compression. It throws away detail that the eye is unlikely to notice, especially fine colour variation, and in return produces small files. That makes it the standard for photographs from cameras and phones. The trade-off is that each time a JPEG is saved, a little more information is lost, and sharp edges such as text or line art can show blocky or fuzzy artefacts around them.
PNG uses lossless compression. Every pixel is kept exactly, so text, icons, diagrams and screenshots stay crisp. PNG also supports transparency, which is why logos and stickers usually come as PNG files. The cost is size: a photograph saved as PNG is often several times larger than the same photo as a JPEG.
Converting JPEG to PNG
Turning a JPEG into a PNG does not bring back detail that JPEG compression already removed; it simply stores the current pixels without further loss. It is useful when a program requires PNG, when you plan to edit the image many times and want to avoid repeated JPEG losses, or when you want to add transparency later in another tool. Expect the file to grow, sometimes a lot.
Converting PNG to JPEG
Going from PNG to JPEG usually makes the file much smaller, which helps with email attachments, upload limits and slow connections. It works best for photos and screenshots of photos. For screenshots full of text or for line drawings, look closely at the result, as small lettering can look slightly soft. JPEG cannot store transparency, so any see-through areas need a background colour; this converter fills them with white, which suits most documents and web forms.
Quick rules of thumb
Use JPEG for photographs and anything where small size matters more than perfect edges. Use PNG for screenshots, text, charts, logos and images that need a transparent background. If a site gives you a size limit, JPEG is usually the way to get under it. If a site asks for a specific format, simply give it what it asks for; that is exactly the job this tool is for.
Frequently asked questions
Is my picture uploaded anywhere?
No. The image is read and converted inside your browser and the result is saved through your browser's normal download. Nothing is sent to a server and nothing is stored after you close the page.
Does converting reduce the resolution?
No. The converted image has the same width and height in pixels as the original. Converting to JPEG does apply compression, so very fine detail can change slightly.
Why is my PNG bigger than the JPEG I started with?
PNG stores every pixel without loss, so photographs take much more space as PNG. That is normal and does not mean quality was added.
Which other formats are supported?
Only JPEG and PNG. Other files, such as HEIC from some phones, may not open in every browser. For broader format support, try a dedicated multi-format converter.
Where does the converted file go?
To your browser's download folder, under the original name with the new extension. On phones, look in the Files or Downloads app.
How is the web version different from the phone app?
The iPhone and Android apps save the result to the photo library and can share it to other apps; they also offer an optional ad-free upgrade. The web version downloads the file instead.
Limitations of the web version
- One image at a time; no batch conversion
- Only JPEG and PNG are supported
- JPEG quality is fixed and cannot be adjusted
- Image metadata such as camera details and location is not copied to the converted file
- Very large images may be slow or fail on phones with limited memory
Phone app
jpeg/png is also available as an app for phones and tablets: