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How to use this tool

Image Format Converter & Batch File Changer

How to use the image format converter

Back to the tool

One choice — which format comes out — applied to a whole batch at the same pixel size. The three on offer are the three your browser can actually write.

  1. 01

    Add the images you want to convert

    Drop them on the page, use Upload images, or paste one in. Up to 25 MB each · JPG, PNG or WebP — the same three formats going out as coming in, because a browser that can read a format is not guaranteed to be able to write it. Nothing is uploaded; the conversion happens in this tab.

  2. 02

    Pick the output format, then run

    WebP is selected already, and for most batches it is the right answer. Whatever you pick applies to every image in the batch — there is no per-image choice and no quality slider, because squeezing a file down to a size is a different tool. Anything already in the format you picked is skipped rather than re-encoded.

  3. 03

    Read the rows, then take the files

    Names change but pixel sizes do not: photo.jpg becomes photo.webp with no suffix added, since the new extension already tells you what happened. Two inputs that would produce the same name get a number — the second one lands as photo (2).webp in the table and in the ZIP alike. Download ZIP takes the batch; the buttons on a row take one image.

How to read the converter results table

Only two things move here: the extension on the name, and the file size that follows from the new format.

Result table columns

Image
The thumbnail and the name you will get — the original name with a new extension, and a number in brackets if another row already claimed that name. A second line appears underneath when the row has something to report.
Dimensions
The same number on both sides of the arrow. Changing the container does not change how many pixels are in it; if you want fewer, that is a different tool.
File size
Before and after. This is where the point of the exercise shows up — and it can go the wrong way, which the second line under the name will tell you about.
Result
One badge per row, and two of them are green. Converting nothing because the image was already in that format is a correct outcome, not a failure.
Actions
Download and copy on a row that produced a file, Retry on a row that failed, nothing on a row that was skipped. Copying always puts a PNG on the clipboard whatever the row says, so use the download button when the format is the whole point.

Result badges

Processing…
This image is being worked on right now. Images are processed one at a time, so exactly one row carries this badge during a run.
Done
The image was re-encoded into the format you asked for and the file is ready. Every image that reaches this point produces a file, even one that came out larger.
Unchanged
The image was already in the format you picked, so it was handed back untouched. Re-encoding it would have cost a little quality to produce a file you already had, so the tool declines — which is why a mixed batch normally finishes with a few of these. These rows are also left out of Download ZIP, since there is no new file to put in it; the original is already on your machine.
Failed
The image could not be drawn — hover the badge for the reason. Almost always the browser ran out of room for an image that large, which is a limit of the machine rather than of your file. Retry reruns only this row.

Which format to pick

WebP
The default, and the right answer unless something below applies. It keeps transparency like PNG and compresses photographs like JPEG, and on photographs the gap is wide: two measured here each went from 71 kB to 22 kB. Flat graphics are where it is least certain — a screenshot full of text can come out larger than the PNG you started with, and the row will tell you so. Every browser in current use can display it.
JPEG
For photographs headed somewhere that will not take anything newer — an old CMS, a print shop, a form with a strict upload filter. It has no transparency at all, so anything see-through in your image comes out solid white. That is a deliberate choice here: left alone, the browser fills those pixels with black.
PNG
For flat graphics with hard edges — logos, diagrams, screenshots with text — and for anything that has to stay lossless. Expect the file to grow: a photograph converted here came out more than three times its original size, because PNG stores every pixel exactly instead of approximating.

The second line under a file name

Already WebP.
Paired with the unchanged badge: this image was already what you asked for. Nothing was decoded and nothing was written, so the row costs you no quality — it simply has no file to give you.
Larger than the original.
The new file is heavier than the one you put in, and you still get it, because you asked for a format rather than for a size. Usually it is a photograph converted to PNG, or a screenshot full of text converted to WebP — both cases where the format you started from was already the tighter fit for what is in the image. There is no matching line when a file gets smaller: the two size columns already say so.
Saved as PNG because this browser can’t save WebP.
Your browser could not write the format you picked, so it quietly produced a PNG instead and the tool tells you rather than letting you find out later. The name carries .png to match what is actually in the file, and this line takes precedence over the one above it, because getting a format you did not ask for matters more than the file size.