How to convert dozens of images at once

Need to convert a folder of photos or graphics, but do not want to open and save each file separately? You can process a batch of up to 50 images at once, as long as they are in a supported format.

The Image Converter works in your browser and supports JPG, PNG, WebP, GIF, BMP, ICO, and TIFF. This guide covers how to convert a batch, which format to choose, and what to try if a file will not convert.

Convert a batch of images

1. Open the Image Converter.
2. Select the images you want to convert from your device. You can select multiple files in the file picker. The tool accepts up to 50 images in one batch.
3. Choose the format you want for the converted images. Pick one output format for the batch, based on how you plan to use the files.
4. Start the conversion, then save the converted images to your device when they are ready. Check a few files before moving or deleting your originals.

If you have more than 50 images, convert them in separate batches. For example, 120 images can be handled as three batches of 40. Keeping each batch smaller can also help if the source files are very large or the browser slows down.

Choose the right output format

The best format depends on what the image contains and where you will use it. Changing formats can affect transparency, animation, file size, and image quality, so keep a copy of the originals until you have checked the results.

Choose JPG for photographs

JPG is widely supported and often makes photos smaller than formats such as BMP or TIFF. It uses lossy compression, which means some image detail is discarded to reduce file size. Each time an image is saved as JPG, some quality may be lost. JPG also does not support transparent areas, so transparent parts of an image will not remain transparent in this format.

Choose PNG for transparency and crisp graphics

PNG keeps sharp edges and supports transparent backgrounds, which makes it useful for logos, screenshots, icons, and graphics with text. It does not use the same kind of lossy compression as JPG, but photo files can be larger. Choose PNG when retaining transparency or clean edges matters more than getting the smallest file.

Choose WebP for web images

WebP is a common choice for images used on websites because it can produce smaller files than PNG or JPG while supporting transparency. Some older programs and workflows may not accept it, so check that the people or apps receiving the images can open WebP files.

Keep GIF for simple animation

GIF can contain animation and is still used for short looping graphics. It has a limited color palette, so it is usually a poor choice for detailed photographs. If you convert an animated GIF to a format intended for still images, do not assume the animation will carry over.

Use BMP, ICO, or TIFF for specific needs

BMP files are often large and are mainly useful when a particular program requires that format. ICO is used for icons, such as application or website icons. TIFF is common in print, scanning, and image-editing workflows where a larger file is acceptable. These formats are not automatically better for sharing online, so choose them when your destination calls for them.

If a batch will not convert

1. Check the batch size. The Image Converter accepts up to 50 images at once. Split a larger selection into smaller groups and try again.
2. Try one image by itself. If the batch fails, a particular file may be damaged or use an unsupported encoding. Convert the files individually to find which one causes the problem.
3. Use a smaller batch for large files. High-resolution photos and large TIFF or BMP files can use a lot of browser memory. Try a few files at a time and close other tabs if your browser becomes slow.
4. Confirm the file is actually an image. A filename ending in .jpg or .png does not guarantee that the contents are a valid image. Re-export the file from the app that created it, or ask for a fresh copy.
5. Check the destination format. If the converted image has no transparent background, the output format may not support transparency, as with JPG. Convert the original again to PNG or WebP if you need transparency.

Keep the originals until you check the results

Conversion is not just a filename change. A file renamed from .png to .jpg is not necessarily a JPG image, and an app may not be able to open it. Use a converter to create a properly encoded image in the format you need.

After a batch finishes, open a few converted files and check that they look right. Pay particular attention to transparency, animation, and small text or fine details. The Image Converter processes files in your browser, and your images stay on your device.