Fly Photos replaces the discontinued Picasa viewer on Windows
A blazing fast ultra-light photo viewer replacement for Windows. Works similar to Picasa Photo Viewer.
At a glance
- What is it?
- Fly Photos is a WinUI 3 photo viewer for Windows that opens the formats the old Google Picasa Photo Viewer handled and adds a configurable keyboard and mouse layer, RAW decoding and a fly-through mode. It is Windows only, ships as a paid Store app or a free unsigned MSI, and its licence is a custom file you have to read.
- Who is it for?
- Adopt Fly Photos if you are on Windows, you miss what Picasa Photo Viewer used to do, and you want camera RAW, PSD, HEIC, AVIF and animated formats opened by a viewer you can tune. Do not adopt it on macOS or Linux, do not rely on the GitHub MSI for signed binaries, and do not expect any scriptable or command line interface, since every feature is reached through the window and the Settings panes.
- Can I use it commercially?
- Check first. The repository uses a licence we do not classify automatically, so read its LICENSE file before any commercial use.
- Is it still maintained?
- Yes. The repository last received commits 15 days ago.
- What is it written in?
- Mainly C#, according to GitHub's language statistics.
Answers come from the project's GitHub data, last synced on October 25, 2026, and from our analysis. They are not legal advice.
Editorial analysis
A viewer built around the gap Picasa left
Google Picasa Photo Viewer is discontinued, and Fly Photos positions itself as its modern replacement on Windows. The README calls it one of the fastest photo viewers for Windows and describes it as a replacement for the now-discontinued Picasa Photo Viewer.
The stack explains the shape of the application. It is built with WinUI 3, WinRT and Win2D, and it ships as a Native AOT build, which is what the README means by instant startup. The audience is Windows users who look at large folders of photographs: the caching is in-memory and disk based, and the fly-through mode exists because holding an arrow key should scroll a folder of thousands of images without loading spinners appearing between frames.
It is also a Windows application in the strict sense. The system requirement is Windows 10 version 1809, build 17763, or newer, on x64 or ARM64, and there is no build for any other platform in the repository.
The source lives in a Src directory with a Misc directory beside it, and the repository also carries a FAQ.md and a CONTRIBUTING.md. The project has no releases tagged on GitHub for the source itself; the published artefacts are the Store app and the MSI files attached to releases.
The Store build is paid and signed, the MSI is free and unsigned
There are two ways to install the application and the difference is not cosmetic. The README puts it in a table.
The Microsoft Store version is paid and updates itself. The GitHub MSI is free, but updates are managed by you and the binary is not signed. Both are the same app with the same features, so the choice is about trust and convenience: a signed package that Microsoft certifies and updates on its own, or an installer you control.
Installing from the Store is a click on the store listing. Installing from GitHub means downloading the MSI for your architecture, x64 or ARM64, from the releases page, and running it. The project states that buying the Store version is the best way to support ongoing development, and it also accepts sponsorship through GitHub Sponsors, with a promo code sent by email in return.
The unsigned MSI is the part to think about twice. Windows will warn on an unsigned installer, and in a managed corporate environment a package that is not signed by Microsoft or by your own organisation may not be installable at all.
Three ways of opening photos are documented once the application is installed. You can right-click an image and pick Fly Photos under Open with, launch it from the Start menu and browse with the file picker, or make it the default handler so a double click opens the image.
Formats: whatever Windows Imaging Component has, plus a good deal more
The base format support is delegated to the operating system. Anything the Windows Imaging Component handles works, which covers JPEG, PNG, TIFF, BMP, camera RAW and any format you have a WIC codec installed for.
On top of that sits an extended list: PSD with transparency, HEIC and HEIF, AVIF, SVG, GIF, APNG, animated WebP and DDS. Multi-page TIFF and multi-frame ICO are handled with page by page navigation, so you can step through the frames inside a single file rather than opening each one.
The camera RAW handling is the more interesting part. The decoder order is configurable: Rawler is described as the fastest, WIC uses the system codecs, and ImageMagick gives the best compatibility. You can also choose to decode the real RAW data instead of the embedded JPEG that most cameras write into the file, which is the difference between a quick preview and the actual sensor data.
That flexibility has a cost in dependency terms. ImageMagick is an external program, so the best compatibility path is only available where ImageMagick is installed, and the fastest path depends on Rawler being present. The README does not describe how these decoders are bundled or located.
Fly-through mode and the Explorer connection
The viewing experience borrows the Picasa idea of a transparent background so the image floats over the desktop, and the README also lists Mica, Acrylic, Frozen Glass or a solid colour of your choice. Light, dark and system themes are all available. Pan, zoom and rotation are smooth, with optional sticky zoom stops, and a thumbnail strip with adjustable size and selection colour sits alongside.
A photo info panel exposes EXIF and camera metadata. You decide whether pan, zoom and rotation reset, are remembered per photo, or carry over while you navigate, which is the kind of detail that separates a viewer you tolerate from one you keep open all day. Multi-monitor support remembers the last monitor you used, and the window can start maximized, full screen, or in the state you left it.
The Explorer integration is the other half of the performance story. The README says Fly Photos follows Explorer's sort order and filtering, including Recent and Search, so the folder you browse inside the viewer matches what you would see in the file manager.
Right-clicking inside the application opens the real Windows Explorer context menu rather than a cut-down imitation, which is a small decision that saves a lot of friction when you want rename, share or open file location.
Every shortcut is a setting, but a few mouse behaviours are fixed
The control layer is unusually thorough for a viewer. Every command in the keyboard table can be rebound in Settings, Keyboard, except Esc and Del, and the README is explicit that a binding you change is stored per user, so a future release keeps your choices rather than resetting them.
The defaults cover a lot of ground: arrows for next and previous photo, Home and End for the first and last, Alt with arrows to step through pages of a multi-page TIFF, Page Up and Page Down for step zoom between fit, 100% and 400%, A for actual size, F to fit to the window, L and R to rotate, F11 for full screen, I for the info panel, and the file group with Ctrl+C to copy, Del to delete, F2 to rename, P to print, S to share and W to open the file location.
The mouse table is where the trade-off appears. Wheel scroll can zoom or navigate, wheel click can toggle full screen, and the back and forward buttons can navigate or step zoom. But Ctrl with the wheel always zooms, Alt with the wheel always navigates, tilt wheel movement always navigates, and Ctrl with a drag always moves the window. Those rows are marked as fixed, and the README says so plainly.
A precision touchpad gets two finger swipe navigation and pinch to zoom. The application is localized in 20 languages including a right to left layout for Arabic.
Recent releases show what is being worked on
The release notes are a good indicator of the current direction. Version 2.7.2, published on 2026-08-29, added customizable shortcuts. Version 2.7.3 on 2026-09-30 made it possible to open very large images, those greater than 16384 pixels, which is the size limit that stops many decoders. Version 2.7.4 on 2026-10-13 added touchscreen pinch to zoom and a fit window to photo option. The last push to the default branch was on 2026-10-13 and the repository is not archived.
Two of those three releases are about input handling, which matches how the application is used: people point at photos rather than type at them.
The licensing story needs attention. The licence identifier on the GitHub repository points to a custom licence that GitHub could not classify, and there is a LICENSE file in the repository that governs the terms. For an application you install on your own machine this is mostly a question of redistribution and of what you may modify, and for anyone repackaging Fly Photos or shipping it inside another product the file has to be read first. That is a licensing fact rather than legal advice.
For a viewer, upgrades are cheap in practice: the Store build updates itself, and the MSI route means downloading a new installer and running it, the same pattern the project already documents for a signed package on Windows.
Where Fly Photos does not reach
Three boundaries are worth naming before you commit.
The first is the platform. Windows 10 version 1809 or newer on x64 or ARM64 is the whole support matrix. There is no macOS or Linux build in the repository, so a cross-platform team cannot standardise on it.
The second is the absence of any scriptable surface. The README documents the window, the Settings panes and the keyboard and mouse bindings, and nothing else. There is no command line mode, no documented file association protocol, and no way to drive the viewer from a script to build a contact sheet or export a batch. If your workflow needs that, the application is a viewer for humans and nothing more.
The third is the MSI trust issue described earlier, which is the strongest practical argument for the paid Store build.
There is also a smaller gap in the format story. The RAW decoders named in the README, Rawler and ImageMagick, are external tools, and the documentation does not say whether they ship with the application or must be installed separately. On a machine without them, the WIC path is what you get, and the real RAW data option may not be available.
Set against that, the comparison with the old Picasa viewer is the honest one to make. Fly Photos covers the same job with the same transparent window and thumbnail strip, adds the formats Picasa never handled, and moves the keyboard map into a settings pane.
Editorial conclusion
Adopt Fly Photos if you are on Windows, you miss what Picasa Photo Viewer used to do, and you want camera RAW, PSD, HEIC, AVIF and animated formats opened by a viewer you can tune. Do not adopt it on macOS or Linux, do not rely on the GitHub MSI for signed binaries, and do not expect any scriptable or command line interface, since every feature is reached through the window and the Settings panes. Before you install, read the LICENSE file in the repository, because the licence identifier on GitHub points to a custom licence rather than a standard one, and check whether the Microsoft Store build or the MSI suits you, since only the Store build is signed and updates itself.
Frequently asked questions
What are the system requirements for Fly Photos?
Windows 10 version 1809, build 17763, or newer, on either x64 or ARM64. The application is built with WinUI 3, WinRT and Win2D and ships as a Native AOT build.
How do I install Fly Photos from the Microsoft Store or the GitHub MSI?
The Store version is paid, updates automatically and is signed and certified by Microsoft. The GitHub MSI is free, has user-managed updates and is not signed, and both are the same application with the same features. The MSI for x64 or ARM64 is on the releases page.
How do I set Fly Photos as the default image viewer in Windows?
Right-click an image file, choose Open With, then Choose Another App, pick FlyPhotos and select Always, repeating it for each file type. To change many types at once, use Windows Settings, then Apps, then Default apps and select FlyPhotos.
Can Fly Photos open very large images and camera RAW files?
Version 2.7.3 added support for images greater than 16384 pixels. Camera RAW decoding goes through a configurable decoder order of Rawler, WIC or ImageMagick, with an option to decode the real RAW data rather than the embedded JPEG.
Official sources
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