Image compressor

Check whether the limit is in megabytes or pixels

An upload form may reject a photo because the file is too large, even when the picture looks small on screen. Start with the receiving site’s requirements: the accepted format, the file-size limit, and any minimum or maximum dimensions.

File size is measured in KB or MB. Dimensions are the width and height in pixels, such as 3000 × 2000. The two are related, but they are not interchangeable: two images with identical dimensions can have very different file sizes.

If the site needs the full dimensions, keep them and try adjusting image quality first. If the photo is much larger than it needs to be, reducing its dimensions is another useful option. Check any minimum width or height before doing so.

Choose a format the receiving site accepts

Choose JPG when the receiving site asks for JPEG or JPG. They are names for the same image format. JPG does not support transparency, so this tool fills transparent areas with white.

WebP can keep a transparent background. It is useful when you need that transparency and the destination accepts WebP, but it is not a promise that every WebP result will be smaller than a JPG.

PNG is accepted as an input here, but it is not an output option. A PNG you add will be saved as JPG or WebP. If you must deliver a PNG, this tool will not produce the required format; changing the downloaded file’s extension would not convert it.

Compress a copy and inspect the result

Choose images or drag them into the file area. You can add up to 10 images in one batch. Under Output format, select JPG or WebP, then set Image quality and Longest edge.

Start with the default quality of 80 if you are unsure. Leave Longest edge at Keep original dimensions when you need the existing width and height. A lower quality setting allows more detail to be discarded; the number is not a percentage of detail retained or a target file size.

Select Compress images. Compare each result’s file size with the original and check the output dimensions. Use Download for the images you want to keep; each gets its own file with -compressed added to the name.

Open the downloaded copy at the size at which it will actually be viewed. A thumbnail can hide soft text, blocky edges, or lost detail. If you change the settings, compress again to generate new results. Cancel stops the remaining work, while completed results stay available to download.

Use the longest edge to resize a large photo

Longest edge sets a ceiling for the image’s longer side. The other side changes in proportion, so the image is not cropped or stretched. Images already below the selected ceiling are not enlarged.

For example, a 3000 × 2000 landscape photo becomes 1920 × 1280 when you choose 1920 pixels. The scale is 1920 ÷ 3000, and the same scale applies to the height. This tells you the resulting dimensions, not how many MB the file will occupy.

The options below show the dimensions for that same photo. Choose a size that still meets the destination’s requirements, then compare the actual file size after compression.

Keep small text and important details readable

A photo and a screenshot do not need the same treatment. A landscape photo may still work well at a smaller size, while a screenshot with small text can become difficult to read after resizing.

For text-heavy images, first try keeping the dimensions and adjusting quality modestly. If text becomes fuzzy, raise the quality and compare again. For a large photo, check faces, fine textures, and smooth areas such as skies before deciding whether the smaller file is usable.

Quality 100 does not make this a lossless tool. The image is still encoded into a new file, and changing format or dimensions may change the result. Keep the original for future editing and create new attempts from that original instead of repeatedly compressing a downloaded copy.

Check the limits if an image will not process

The tool accepts still images in JPG, PNG, and WebP. Animated PNG and animated WebP are rejected; GIF, HEIC, and SVG are not supported inputs. If a phone photo is in HEIC, convert it to a supported format before adding it.

The limits apply together. For example, an image can be under 20 MiB and still exceed the 24-megapixel limit. If a file exceeds the pixel limit, resize it in another image editor before trying to add it here.

If the browser cannot produce your chosen output format, try JPG. A file that cannot be decoded may be incomplete or damaged; check that the original opens normally before trying again.

Questions about the downloaded image

Further reading

• MDN: HTMLCanvasElement.toBlob()Explains browser image output formats and the quality parameter used when encoding a new image.
• Google: WebP overviewDescribes the WebP format, including transparency. Format capabilities do not mean every mode is available in this tool.