Why a screenshot gets larger after PNG conversion

You converted a screenshot to PNG and the new file is bigger than the original. That can happen even when the picture looks exactly the same. PNG is not a universal file-size reduction format, and converting an image cannot recover detail that was discarded when it was first saved.

Use the Image Converter to make a PNG copy in your browser, then compare the files and choose a format based on how you plan to use the screenshot.

Convert and compare the screenshot

1. Open the Image Converter and choose the screenshot file. You can convert up to 50 images at once.
2. Select PNG as the output format and convert the file.
3. Save the converted image, then compare its file size with the original. Check the image dimensions too, so you know whether both files have the same width and height.
4. Open both images at the same zoom level. Look at small text, sharp edges, gradients, and any transparent areas to see whether the conversion changed their appearance.

File size is usually shown in the file's properties on Windows or in the Finder's Get Info window on a Mac. Make sure you compare the actual image files, not a thumbnail, preview, or a copy that an app has resized.

What the result means

The PNG is bigger than a JPEG or WebP file

This is common. JPEG and many WebP files use lossy compression, which reduces file size by changing or removing some image information. PNG uses lossless compression: it keeps the pixel values it receives, but it may need more bytes to store them. A screenshot with a photo, soft shadows, or complex gradients can therefore grow when saved as PNG.

PNG often works well for screenshots with crisp text, flat colors, and interface elements. But the word screenshot does not guarantee that the image will compress especially well as PNG. A screenshot of a photo or video frame has much more variation than a simple screen of text.

The PNG is bigger than the original PNG

PNG files can be encoded in different ways. One file may use a limited color palette or efficient compression, while another uses a fuller color representation or different compression settings. Re-encoding a PNG can make it larger even though PNG is lossless. Extra image data, such as a color profile or other metadata, can also affect the size.

If both files have the same dimensions and look the same, the size difference usually reflects how they were encoded, not a change in image quality.

The PNG looks the same but is much larger

The original may have used lossy compression. When that image is converted to PNG, the converter stores the pixels it received without adding back the information that the original compression removed. The PNG can be larger without looking sharper. It is a lossless copy of the already-compressed image, not a restoration of the original screenshot.

The image dimensions or appearance changed

Changing the file format alone should not require different dimensions. If the converted image is smaller, cropped, or noticeably different, check whether the source was a preview or resized copy, or whether another export step changed the image. Compare the same original file again before judging the conversion.

How to keep the file size under control

1. Keep the original file. If you may need to edit or convert the screenshot again, keep the untouched source. Converting a JPEG to PNG does not undo the JPEG compression.
2. Choose a format for the content. PNG is a sensible choice for sharp interface text, diagrams, and images that need transparency. For a screenshot dominated by photography, JPEG can be smaller, but its lossy compression may blur fine text or add artifacts. WebP is another option when the apps or websites you use accept it.
3. Check whether transparency matters. PNG can preserve transparent areas. If the screenshot has no transparency and the receiving app does not need it, another format may meet your needs with a smaller file.
4. Reduce unnecessary image area. If you only need part of the screen, crop the image in an editor before sharing it. Fewer pixels generally mean less image data to store. Keep a full-size original if you might need the rest later.
5. Do not convert repeatedly. Each lossy conversion can discard more detail. Convert from the best available original and avoid saving the same image repeatedly as JPEG.
6. Use the size that fits the destination. If a website, form, or message has a file-size limit, follow its stated format and size requirements. Do not reduce quality just to make a PNG smaller if the destination specifically needs sharp text or transparency.

Why PNG can be useful despite the larger size

PNG compression looks for patterns in the image and stores them without discarding pixel information. Flat color areas and repeated patterns can compress efficiently. Detailed photos contain many small changes from pixel to pixel, so there may be fewer patterns for PNG compression to use.

For a screenshot that contains small labels, charts, or menus, keeping crisp edges may matter more than saving space. For an image being sent in a message or placed on a page with a strict upload limit, a smaller format may be more practical. The right choice depends on the image and where it will be used, not simply on which file extension sounds more compressed.

The Image Converter runs in your browser, and the files you open stay on your device.