How to Convert Many Images at Once to JPG, PNG or WebP
Converting images one at a time is slow. The batch converter takes a pile of JPG, PNG or WebP files and gives them back in one format, in a single ZIP, once you know a few details.
Add JPG, PNG or WebP files, pick a target format and download everything in a ZIP.
Convert a whole folder in one pass
- Open Batch Image Converter and add your files. It accepts JPEG, PNG and WebP, and you can mix them in one go.
- Under Convert all to, choose JPG, PNG or WebP.
- Set the options that appear for that format: a Quality slider (10 to 100, default 85) for JPG and WebP, and a Background color box for JPG.
- Press Convert All, then Download All (ZIP). A single file downloads on its own as Download Image.
The ZIP is called converted-images.zip and each file keeps its name with the new extension, so team-photo.png becomes team-photo.jpg. When it finishes, the result line reads "Converted 24 image(s) to JPG."
Which target format for which job
| Target | Options shown | Pick it for |
|---|---|---|
| JPG | Quality and background colour | Photos for email, forms, anything that must open everywhere |
| PNG | None, always lossless | Screenshots, logos, graphics that need sharp edges or transparency |
| WebP | Quality | Website images where smaller files matter |
For help choosing, read JPG vs PNG vs WebP. In short: photograph, go JPG or WebP; flat graphic or transparent logo, go PNG or WebP.
The background colour box explained
JPG cannot store transparency. When you choose JPG as the target, the tool paints the whole canvas in the colour you give, #FFFFFF (white) by default, and draws the image over it. Transparent areas of a PNG or WebP therefore become that colour. Without this step the transparent areas can turn black in some programs, which is the usual reason a logo suddenly looks wrong after saving as JPG.
Pick a colour that matches where the image will sit. A logo going onto a dark slide needs a dark fill, not white. Enter the code in the form #RRGGBB. The field only matters for JPG; for PNG and WebP, transparency is kept as it is. More on this problem in converting PNG to JPG without a white background.
Mistakes that cost people a batch
- Name clashes. The new name is the old name minus its extension plus the new one. If a folder holds
logo.pngandlogo.jpgand you convert everything to WebP, both becomelogo.webpand the ZIP can keep only one of them. Rename duplicates first. - Unsupported formats. The file picker accepts JPEG, PNG and WebP. For HEIC use HEIC to JPG, and for AVIF use AVIF to JPG.
- Converting to the same format. Choosing JPG for a folder of JPGs does not simply copy the files. They are re-encoded at your quality setting, so quality can drop and file size may change.
- Animated WebP. Conversion goes through a canvas, so only one frame survives.
- Mixed content in one run. Photos and screenshots rarely need the same quality. Split them into two runs.
What to expect for sizes and metadata
Dimensions never change. A 4000 x 3000 image is still 4000 x 3000 after conversion, so a batch of phone photos stays heavy even as WebP. If your real goal is smaller files for an upload limit, combine this with Resize Image or follow the upload-limit guide. Converting from JPG to PNG makes files larger. Converting PNG screenshots to JPG usually makes them smaller but softens text edges.
EXIF data such as camera model and GPS position is not written to the new files, because every image is redrawn on a canvas. That is a side effect worth knowing, and it is explained further in how to remove EXIF data from photos.
A worked example: a mixed folder from a client
Say a client sends 30 images: 18 phone photos as JPG, 8 logos and screenshots as PNG, and 4 WebP pictures saved from a website. Your design software wants PNG and your email system wants JPG. Run it twice. First, add the 8 PNG graphics and convert to JPG with a white background if they have transparency and white suits your layout. Second, add the photos and WebP files and keep them as they are, or convert only the WebP set to JPG at 90 so they open anywhere. Two short runs with the right settings beat one run that is wrong for half the folder, and each ZIP is easy to check by opening it with Archive Viewer.
Limits and privacy
There is no fixed cap on the number of images, but your browser has to hold them in memory, so hundreds of full-resolution photos on a phone may stall. Process in groups of 20 to 50 if the page becomes slow. Images are converted in your browser and not uploaded, and the ZIP is built there too with the JSZip library, which loads from a CDN when the page opens.
If you only have one format pair to do, a dedicated page can be quicker, such as WebP to PNG or PNG to JPG.
Frequently Asked Questions
Which formats can I put in and get out?
You can add JPEG, PNG and WebP files and convert them to JPG, PNG or WebP.
What does the background colour do?
When converting to JPG, transparent areas are filled with that colour, white by default, because JPG cannot store transparency.
Why does my ZIP have fewer files than I added?
Files with the same name but different extensions end up with the same new name and overwrite each other. Rename them before converting.
Is there a limit on how many images I can convert?
No fixed limit. Browser memory is the practical limit, so work in smaller groups if the page slows down.
Does converting change image dimensions?
No. Width and height stay the same, so use Resize Image to reduce pixel size.
Are my images uploaded anywhere?
No, conversion runs in your browser. The JSZip library loads from a CDN when the page opens, but your images are not sent.