Online vs Desktop HEIC Converters: Which Should You Use?

Choose a desktop app if you convert HEIC every week, need scripts or saved presets, or must keep very large photos (over 16,777,216 pixels, such as 48-megapixel shots) at full size. Choose an online converter if you convert now and then, switch between computers and phones, or cannot install software. But “online” covers two different things: upload-based converters send your photos to a server, while a browser-based converter such as heicly converts them on your device. That difference matters more than online versus desktop.

Three kinds of HEIC converter

	Upload-based online converter	Browser-based converter (heicly)	Desktop app
Where photos are converted	On the service’s servers	In your browser, on your device	On your computer
Install	Nothing	Nothing	An app, sometimes plus codecs
Devices	Any device with a browser	Up-to-date Chrome, Edge, Firefox or Safari, including on phones	The systems the app supports
Without internet	Does not work	Works after one conversion while online	Works once installed
Repeated or scripted jobs	Manual each time	Manual each time; naming and output size settings are remembered	Presets, scripts, right-click conversion, depending on the app

Third-party details below were checked on their official pages on 31 October 2026; sources are listed at the end. We have not measured conversion speed, so this article does not compare it.

Where your photos go

Upload-based converters say so on their own pages. FreeConvert says it uploads files and deletes them “automatically after 8 hours”. CloudConvert’s privacy policy says files are “transferred to and temporarily stored on CloudConvert’s servers” and deleted after 24 hours at the latest. Until then, you rely on the service to delete them.

Desktop apps convert on your computer. CopyTrans HEIC, for example, says “All conversion happens locally on your PC!” heicly also converts locally, but inside a browser tab: there is no upload step. To check any converter yourself, see how to tell whether a HEIC converter uploads your photos. For the upload services’ limits and retention side by side, see free HEIC to JPG converters compared.

Installing, and on which devices

• Mac: Preview is built in. Choose File > Export and pick JPEG; to convert several images, open them in one window and select them in the sidebar.
• Windows: the Photos app opens HEIC after you install two Microsoft Store extensions. HEIF Image Extension is free; HEVC Video Extensions costs US$0.99 in the US Store, and Microsoft says “You’ll need both”. The extensions do not convert files to JPG by themselves.
• Converter apps: IrfanView (Windows) needs a HEIC codec, which its FAQ lists. CopyTrans HEIC (Windows) asks for administrative privileges during installation. XnConvert runs on Windows, macOS and Linux.
• In the browser: nothing to install.

Desktop apps are tied to the systems they support; a browser converter works on whatever computer or phone you are using, including one where you are not allowed to install software.

Working offline

An installed app works without a connection. An upload-based converter needs the internet for every file. heicly sits in between: convert one photo while online, and your browser keeps heicly’s converter page (such as the offline converter) and the conversion engine, so later conversions there work offline. This blog page itself is not stored for offline use. On a first visit, stay online for about 30 seconds after the JPG is ready. Browsers can delete stored site data when storage runs low or when you clear browsing data, so try it once before you rely on it, for example before a flight.

Large batches and very large photos

• heicly: no fixed number of photos. Up to three convert at a time and the rest wait in a queue; your device’s memory sets the practical limit, because the JPGs and the ZIP are held in the page’s memory.
• Very large photos: heicly resizes images above 16,777,216 pixels proportionally, for example 48-megapixel photos, and the page tells you when it does. If you need every pixel of such photos, convert them with a desktop app and check the output size.
• Desktop apps: CopyTrans HEIC converts “up to 100 images in one go” from the right-click menu; XnConvert and ImageMagick process whole folders.

Automation and repeated jobs

This is where desktop tools pull ahead. XnConvert saves presets you can reuse for later batches. ImageMagick runs from the command line; when it is built with HEIC support (libheif), a single line such as magick mogrify -format jpg *.HEIC converts a folder and can go into a script. IrfanView has batch processing, and CopyTrans HEIC adds conversion to the right-click menu.

A browser converter is manual: you choose the files each time. heicly remembers your download file-name setting and output size in your browser, but it does not watch folders or run on a schedule. For step-by-step batch methods, see 4 ways to batch convert HEIC to JPG.

Location and other photo details

Converters differ in what they copy into the JPG. CopyTrans HEIC says it keeps “your original EXIF data (date taken, geolocation)”. heicly’s JPGs keep the date taken and camera details, but location (GPS) is left out unless you turn on “Also keep location (GPS)”. If you share converted photos publicly, check what your tool keeps.

Which to choose

• A few photos now and then, any device: a browser-based converter. Your photos are not uploaded and there is nothing to install.
• Many photos every week, or the same settings every time: a desktop app with presets or scripts, such as XnConvert or ImageMagick.
• Photos over 16,777,216 pixels that must stay full size: a desktop app.
• Photos already on your Mac: open them in Preview and export.
• Documents, audio and video too: upload services such as CloudConvert handle many file types; check their retention terms first.

Try heicly

Choose one or more HEIC photos and download each JPG or one ZIP. After this first conversion, heicly’s converter pages, such as the offline converter, work offline in this browser.

Sources

Checked on 31 October 2026: FreeConvert’s HEIC to JPG page; CloudConvert’s privacy policy; CopyTrans HEIC; Apple’s Preview User Guide; Microsoft’s HEIF Image Extension and HEVC Video Extensions Store pages (US Store) and support article; IrfanView and its FAQ; XnConvert; ImageMagick’s download page, mogrify and formats pages.