Resizes images without changing the format. Five modes, and the ones that keep the aspect ratio are the defaults — stretching an image is almost never what anyone wants, so it is opt-in and warned about.
The five modes
Width — set a width, the height follows to keep the proportions. The most common case: "make these 1200 pixels wide for the blog".
Height — the same in the other direction.
Percentage — halve everything, or double it. Useful for a batch of mixed sizes where a fixed width would be wrong for some.
Fit inside a box — scale down until the image fits within a width and height, keeping proportions. This is what you want for a mixed folder of portrait and landscape photos. It never enlarges.
Exact — force both dimensions. This stretches the image if the ratio differs, and you get a warning saying so.
Enlarging does not add detail
Fit-inside mode never enlarges, which is deliberate — a folder of mixed sizes should not have its small images blown up.
Smooth scaling, and when to turn it off
Turn it off for pixel art, sprites and QR codes. Those want nearest-neighbour scaling, where each pixel becomes a hard block. Smoothing a piece of pixel art doubled in size turns crisp squares into mush.
Metadata is removed, which is usually the point
For a photo you are about to publish this is a feature. A JPEG straight off a phone can carry the exact coordinates of where it was taken, and stripping that before it goes anywhere public is good practice — the conversion does it as a side effect.
The one piece of metadata that is honoured before being dropped is the orientation flag. Phones store photos in the sensor's native orientation with a tag saying which way is up; ignoring it produces sideways pictures. It is applied to the pixels, so the result is upright without needing the tag.
If you need the EXIF preserved, this is the wrong tool — a converter that re-encodes cannot keep it.
Other names for this
Also searched as “image resizer”, “resize photo”, “change image dimensions”, “scale image”.
Questions
- Will the aspect ratio be kept?
- In every mode except "Exact", yes. Exact stretches to fit and warns you when the ratio differs.
- Can I make an image larger?
- Yes, but no detail is added — enlarging interpolates and softens. Fit-inside mode deliberately never enlarges.
- My pixel art looks blurry.
- Turn off smooth scaling. Pixel art needs nearest-neighbour, where each pixel becomes a hard block.
- What format does the result come out as?
- PNG, so nothing is lost in the re-encode. Use Compress Image if you want JPEG and a target file size.
- Can I convert a whole folder of images?
- Yes. Drop as many files as you like, or a whole folder. Each keeps its original name with the new extension —
IMG_4032.heicbecomesIMG_4032.jpg, neverconverted_1.jpg— and you can download them individually or as a ZIP. - Are my photos uploaded?
- No. The decoding and re-encoding happen in this tab using the browser’s own image support. Photos are personal in a way most files are not, and none of them is transmitted. Turn your Wi-Fi off and the converter keeps working.
- How large an image can I convert?
- The practical ceiling is the browser’s canvas limit, about 268 million pixels in total area — roughly 16,000 × 16,000. Above that you get a clear error rather than a silent failure, and resizing first is the fix. File size itself is limited only by your device’s memory.