Free online PART to JPG converter

A browser or download manager may leave an image with a .part suffix while the transfer is incomplete, but image editors, websites, and messaging apps require a finished image file. Complete the download first, then convert the image to JPG only if its original format is different.

What the PART format is

.part is a temporary filename suffix, not a standardized graphics format. Browsers and download managers, including Firefox and other file-transfer software, use it while writing a download to disk.

The contents may be an unfinished JPEG, PNG, GIF, TIFF, archive, document, or another binary file. The suffix does not identify the original format. After a successful transfer, the application normally removes .part and restores the original extension; interrupted downloads may retain the suffix.

Do not convert or rename an active .part file. Missing download bytes cannot be recreated by changing its filename.

What the JPG format is

JPG, also called JPEG, is a compressed raster-image format supported by operating systems, web browsers, phones, image editors, and most sharing services. Its lossy compression creates relatively small files for photographs and other continuous-tone images.

JPEG does not store transparency and can introduce blocking, ringing, or blurred detail when heavily compressed. PNG is usually better for transparency, screenshots, diagrams, and sharp text; TIFF or the original RAW file is better for archival editing. Repeatedly saving a JPEG as another JPEG adds further lossy compression.

How to convert a completed download

1. Open the browser or download manager that created the file and resume the transfer. Wait for a completed or verified status before moving or renaming the file.
2. Check whether the program removes .part and restores the source extension. If it does, use that completed file rather than the temporary one.
3. If the file still ends in .part, identify its contents. On macOS or Linux, run file filename.part. On Windows, use a file-identification utility such as TrID, or check the format specified by the download source. A file signature can identify a format, but it does not prove that a truncated file is complete.
4. Open a copy in an image viewer. If the complete file is already JPEG data, change only the final filename extension to .jpg; conversion is unnecessary and would cause another JPEG save.

Convert with desktop software

For a completed PNG, GIF, TIFF, WebP, or other readable image, use an image editor or batch converter such as GIMP, Paint.NET, XnConvert, or ImageMagick. In a graphical editor, open the source and choose File → Export As or the equivalent export command, select JPEG, set the output filename to .jpg, choose the destination, and save.

XnConvert supports batch processing on Windows, macOS, and Linux: add the completed files under Input, choose JPG - JPEG under Output, set the destination and quality, then start the conversion.

ImageMagick can convert a recognized, complete source image from a terminal:

magick input.png -quality 90 output.jpg

Replace input.png with the actual source filename and format. Do not pass an incomplete .part file unless an image utility confirms that it is readable and the download is known to be complete.

Convert without installing software

You can use the free converter on 101convert.com after the download has finished. Upload only a complete image, select JPG as the output format, choose the available quality setting, and download the result. A converter can change a supported image format, but it cannot reconstruct data missing from an interrupted download; private images should be uploaded only when the site’s handling terms are acceptable.

Quality and compatibility limits

Renaming picture.part to picture.jpg changes only the name. An incomplete file will normally be rejected or produce a damaged image because its missing data and closing image structures are unavailable.

If the original file is a complete JPEG with an incorrect temporary suffix, renaming it preserves its existing image data. If the original is PNG, TIFF, WebP, RAW, or another format, exporting to JPEG discards format-specific information and removes transparency where applicable.

A JPEG quality setting around 85–95 is a practical starting range for photographs, although the visible result and file size depend on the encoder and image content. Keep the original source when quality or future editing matters. A checksum supplied by the download source can verify that the completed file was transferred without alteration.