If you need to convert multiple JPG/JPEG files into PNG quickly, the fastest method depends on your batch size, device, and whether you can upload files online.
Method 1: Fastest at scale (ImageMagick — CLI)
ImageMagick mogrify is built for bulk processing; it can overwrite originals, so work on copies or output to a new folder.
Convert all JPGs in a folder to PNG (safe output folder)
mkdir -p out
magick mogrify -path out -format png-jpg
Convert both .jpg and .jpeg
mkdir -p out
magick mogrify -path out -format png *.jpg-jpeg
Best for: massive folders, privacy, repeatable workflows.
Method 2: Fastest no-install on Mac (Preview)
MacRumors documents Preview’s batch conversion and the Option (⌥) key trick to reveal extra export formats.
Steps
- In Finder, select all JPGs → Open With → Preview
- In Preview sidebar: Cmd + A (Select All)
- File → Export Selected Images…
- Choose PNG → pick destination folder → Export
Method 3: Fastest GUI bulk converter (XnConvert)
XnConvert is positioned as a fast, cross-platform batch image converter and supports many batch actions.
Steps
- Add files/folder
- Output → Format: PNG
- Choose output folder
- Convert
Best for: bulk conversion + optional actions (resize, rename, compress).
Method 4: Fast online batch (iLoveIMG)
If you want speed with minimal thinking, iLoveIMG explicitly supports converting multiple JPG to PNG at once.
Steps
- Upload/drag multiple JPGs
- Convert
- Download (usually as a bundle/ZIP depending on tool)
Method 5: Online with more control (CloudConvert)
CloudConvert supports JPG→PNG and provides options to control resolution/quality/file size.
Steps
- Upload multiple files
- Adjust settings (optional)
- Convert → download
Common issues (quick fixes)
My PNGs are bigger than the JPGs
Normal. PNG is often larger, especially for photo-like images. If you’re converting for web, consider whether you actually need PNG.
Will JPG → PNG improve image quality?
No — converting doesn’t restore detail already lost to JPG compression. It only changes format/container.
Will JPG → PNG give me transparency?
Not automatically. PNG supports transparency, but a JPG doesn’t contain transparency data.