How to open .JPG files (JPEG photos) on Android, Windows and Linux

Nearly every photo you take, download or get sent ends in .jpg, and most of the time it simply opens. Then a picture saved from a website turns up as .jfif, an old download ends in .pjpeg, or a photo copied from a camera shows up sideways or half grey, and it isn’t obvious what’s going on.

The short answer: they’re all JPEG photos, and Folders opens every one of them in its image viewer on Android, Windows and Linux, for free and offline. Below is what a JPG actually is, how to open it, and what to do when one misbehaves.

What is a .JPG file?

JPEG is named after the Joint Photographic Experts Group, the committee that created the standard in the early 1990s. It was made for photographs, and its trick is lossy compression: when a JPEG is saved, the encoder throws away fine detail and colour information your eye is unlikely to miss. That’s how a 12-megapixel photo fits in a few megabytes. A quality setting decides how much goes; push it too far and you get blocky squares and smudgy halos around text and sharp edges.

Three things follow from that design:

• No transparency. A JPEG always has a solid background, which is why logos are usually PNGs.
• Every save compresses again, so keep the original and edit copies.
• Photos carry hidden details. Cameras and phones store EXIF data inside: camera model, date, exposure, which way up the camera was held, and often the GPS position.

Extension	What it is
.jpg	The usual ending. Three letters, because old systems such as MS-DOS allowed no more after the dot
.jpeg	Exactly the same format with the full name
.jfif	Also the same. JFIF (JPEG File Interchange Format) is the wrapper most JPEGs use; Windows sometimes saves web pictures with this ending
.pjpeg	Usually a progressive JPEG, which appears blurry first and sharpens as it loads; the name comes from “image/pjpeg”, a label older Internet Explorer versions used

How to open a .JPG file with Folders

On Android

1. Download Folders from the download page, install it (Android 7.0 or newer) and allow access to your files when asked.
2. Go to the photo. Camera shots are usually in DCIM/Camera, saved pictures in Download or Pictures. Or type *.jpg in the search box to list every JPG below the folder you’re in.
3. Tap it. Swipe left or right for the other photos in that folder.

If the photo is in another app, such as an email or a chat, use that app’s Open with and pick Folders.

On Windows and Linux

1. Install Folders: the setup program on Windows; deb, rpm, AppImage, Flatpak, Snap or tar.gz on Linux.
2. Find the photo in Folders and double-click it. The arrow keys step through the folder.
3. On Windows the installer also adds Folders to File Explorer’s Open with menu for JPG, JPEG, JFIF and PJPEG files: right-click the photo, choose Open with, then Folders.

What you can do with a JPG in Folders

• Zoom in to check focus.
• Details shows what the camera stored: make and model, when the photo was taken, exposure, aperture, ISO, focal length, lens, and the location if one was saved.
• Edit: crop by dragging any edge or corner, use Adjust for brightness, contrast and saturation, or pick a Filter, then save. Save as copy leaves the original as it was.
• Copy all text copies the words Folders recognises in the photo: a receipt, a whiteboard, a page of notes, a sign.
• Convert to ▸ (select one or many photos, then use the selection or right-click menu) makes copies beside the originals in PNG, WebP, HEIC, TIFF, BMP, GIF, ICO or TGA, and AVIF on Windows and Linux. On a computer, WebP, AVIF and HEIC copies use FFmpeg, which Folders downloads the first time.
• Resize… makes smaller copies for email or a form with an upload limit. Converted and resized copies come out the right way up, whatever the orientation tag said.
• Share it, or Open with another app for anything Folders doesn’t do.

Other ways to open .JPG files

• Windows: the built-in Photos app. Linux: your desktop’s image viewer, such as GNOME’s Image Viewer or KDE’s Gwenview.
• Android: Google Photos or the phone maker’s Gallery app.
• Any web browser: drag the file into a tab.
• GIMP, free on Windows and Linux, when you need proper photo editing with layers.

Problems opening a .JPG file?

The bottom of the photo is grey, or cut off. The file is incomplete: a download or copy stopped early. JPEGs are drawn from the top down, so a short file shows only its top part. Copy or download it again.

It opens sideways in one app and upright in another. The pixels are stored as the sensor saw them, with a tag saying how to turn them, and some apps ignore the tag. A copy made with Resize… or Convert to ▸ has the rotation applied, so it looks right everywhere.

A website won’t accept a .jfif or .pjpeg. The picture is fine; the form just checks the ending. Rename the file so it ends in .jpg. On Windows, .jfif files come from a setting in Windows itself, not from anything wrong with the picture.

Questions people ask

Can I open a .JPG file on Android without Google Photos? Yes. Folders opens JPG, JPEG, JFIF and PJPEG files straight from its file browser, with no account and no internet connection.

Is a JPG file safe to open? A JPEG is picture data, and opening one in an up-to-date viewer is safe. The bigger concern is privacy: a photo can carry the place it was taken. Check Details before you share, and if a location shows, remember it travels with the file.

How do I convert JPG to PNG? Select the photos in Folders and choose Convert to ▸ PNG. The PNG won’t look sharper, because detail the JPEG discarded doesn’t come back, but it won’t lose any more however often you save it.

JPG vs JPEG: what’s the difference? None. It’s the same format; only the length of the ending differs. The same goes for .jfif, and in practice for .pjpeg.

Photos from an iPhone? See how to open HEIC photos. For screenshots and graphics, read the PNG guide, or browse all 382 file types Folders opens.