How to use the image converter
- Choose Single image or Batch mode.
- Drop pictures on the drop zone (Enter opens the file picker) or press Try a sample photo. JPG, PNG, WebP, GIF, BMP, AVIF and SVG files are read.
- Pick Convert to: PNG, JPG, WebP or BMP. For JPG and WebP set Quality. For JPG and BMP choose the color that Fill transparent areas with.
- Single mode shows both sizes at once, then Download converted image. In batch mode press Convert all, then download each file or Download all as ZIP.
How the conversion works
Your browser decodes the picture, redraws it on an HTML canvas and saves it again with canvas.toBlob. PNG is lossless. JPG and WebP are lossy and follow the Quality slider. BMP is written by this page as a 24-bit file: a 54-byte header plus rows of 3 bytes per pixel padded to a multiple of 4, so its size is exactly 54 + (3 x width, rounded up to a multiple of 4) x height. JPG and BMP cannot hold transparency, so those areas take the fill color. Re-saving never adds detail, and metadata such as EXIF and GPS is not copied across. For smaller files try the image compressor or the image resizer. iPhone photos need the HEIC to JPG converter first.
Worked example
Press Try a sample photo. It is a 1200 x 800 pixel JPG of 200.4 KB. In Chrome, Convert to PNG reads 1.66 MB, 749.5% larger, because PNG is lossless and keeps every pixel of a picture that was already compressed. BMP reads 2.75 MB, 1303.2% larger, which is exactly 54 + 3,600 x 800 = 2,880,054 bytes. JPG at quality 90 reads 131.5 KB, 34.4% smaller. PNG and JPG sizes differ a little between browsers, but the BMP size never does.
Limits and edge cases
- An animated GIF is converted from its first frame only.
- Batch mode takes up to 50 images at a time.
- Very large pictures may fail because browsers limit canvas size, and a message says so.
- If your browser cannot create WebP, that option is turned off.
- Files that are not images, or are damaged, are skipped with a message.
Frequently asked questions
Why does my transparent PNG get a white background as a JPG?
JPG cannot store transparency, so transparent areas are filled with a solid color. White is the default, and you can pick another with Fill transparent areas with. Choose PNG or WebP to keep the transparency.
Which image format should I choose?
Use JPG for photos, PNG for logos, screenshots and anything with transparency, and WebP for the smallest files on the web. Choose BMP only when a program asks for uncompressed pixels.
Will converting a JPG to PNG improve the quality?
No. A JPG has already lost some detail, and PNG keeps those pixels exactly as they are. The picture looks the same and the file is usually larger.
Does the quality slider affect PNG and BMP?
No. PNG and BMP are lossless, so the Quality slider is hidden for them. It only applies to JPG and WebP.
Can I convert an iPhone HEIC photo here?
Most browsers cannot open HEIC, so this page will say it cannot read the file. Use the HEIC to JPG converter first, or set the iPhone camera format to Most Compatible.
Sources: Image file type guide (MDN), Bitmap storage (Microsoft).