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Calimero

Small, black, ugly... But powerful!

Calimero is a high-performance Win32 (x86) console application designed to take full control of your Windows Desktop background (Windows 8 and up).

Current version is 4.6.1.0 (19/02/2026).

🥚🍳 Key Features

• Display Modes: Supports all native Windows modes (stretch, center, tile, fit, fill, span) plus custom implementations like cover, alternate, and the upcoming gallery mode.
• Multi-monitor Mastery: Native support for multi-monitor setups. Perfectly handles wide wallpapers, 4K assets, and complex spanning without blurriness.
• Graphic Filters: Apply professional-grade filters via integrated libraries (paintLib, NexgenIPL, FreeImageRE, ImageMagick) and custom built-in effects like GhostTrail, Echo, Pixelate and more.
• Smart Rescaling: Custom algorithms to resize images on-the-fly for the sharpest possible output.
• Deep Customization: Print dynamic text over images, filter by size or wildcards and sort by name, size, etc.
• Hypersonic Loading: Powered by the BerkeleyDB engine to manage thousands of files instantly. No more disk-thrashing or re-scanning directories every time you run it. On a typical laptop, the initial full hard drive scan for images uses less than 16MB of RAM to index and load 40,267 images into a BerkeleyDB table. On later runs (with the table already populated), Calimero averages only about 3,5MB of RAM while running and navigating the 40,267 images.
• Seamless Navigation: Change wallpapers via a configurable timer or global hotkeys.
• Web Fetching: Fetch images directly from the web using free services like Picsum.
• Native & Lightweight: Zero bloated frameworks, zero SLOP, no VIBE-coding. Just pure, "to-the-metal" Win32 C/C++. A small, black and ugly console app, but deadly as a Ninja!
• 100% Free: No telemetry, no hidden connections, no backdoors. Just code.

🍴 Let's Go! (beta testing guide)

• Getting Started:
• Download the Installer from the Releases section and run it.
• The Installer will create a folder named WCHG directly in your C: drive root.
• Once the installation is complete, press Win+R, type CMD and hit Enter.
• When the console windows opens, type CD \WCHG and hit Enter.

• Launch the app by typing Calimero followed by the required parameters (see the Examples section below).

• Basic, Essential Arguments:

• -t : Timeout (minutes) between wallpaper changes.
• -d : Source directory for images.

• -m : Display mode: 1: Stretch, 2: Center, 3: Tile, 4: Fit, 5: Fill, 6: Cover, 7: Span, 8: Alternate (note that the alternate mode has the following sub-modes: 1=stretch, 2=center, 3=tile, 4=fit, 5=fill, 6=cover - append the number directly to the mode, e.g. -m81, -m84, etc.)

• Global Hotkeys:
  The following hotkeys always work, even if the console window is minimized:

• Ctrl + Alt + N: Next image.
• Ctrl + Alt + P: Previous image.
• Ctrl + Alt + X: Remove image from the list and optionally delete it from disk.

• Ctrl + Alt + Q: Quit.

• Quick Help:
  Use the -h option from the command line:
  C:\WCHG>Calimero -h
  Or use the Ctrl + Alt + H hotkey when the program is running and the console is visible.
  As soon as possible I'll terminate the below User Manual section.

• Examples:

• Kill me softly: Use the folder C:\Users[...]Wallpapers (notice the double quotes around the path because it contains spaces), with a 1-minute timeout (-t1) for changing the image, displaying it in center mode (-m2):
  Calimero -d"C:\Users\lpier\Documents\Luca\Pictures\Wallpapers" -t1 -m2

• Span me!: On a multi-monitor setup, use the folder Calimero -d"C:\Users[...]Dual, with a 5-minute timeout (-t5) for changing the image, displaying it in span mode (-m7):
  Calimero -d"C:\Users\lpier\Documents\Luca\Pictures\Wallpapers\Dual" -t5 -m7

• To filter or not to filter: (1) Same as above, but using the alternate mode (-m8) and applying the GhostTrail filter (-fGhostTrail) to the image before displaying it:
  Calimero -d"C:\Users\lpier\Documents\Luca\Pictures\Wallpapers" -t5 -m8 -fGhostTrail
  or using a random graphics filter selection: (2)
  Calimero -d"C:\Users\lpier\Documents\Luca\Pictures\Wallpapers" -t5 -m8 -frandom
  (1) keep in mind that on very large images applying filters may take a bit
  (2) to show a list of the available filters, use the Ctrl + Alt + G hotkey

• Dijkstra mode: Start from the folder C:\Users[...]Pictures and using a recursive search in subfolders (-r) , change image every 3-minutes (-t3), display in fit mode (-m4) and use fast 🐇 loading from table for subsequent runs (-D), not to mention the random order (-o3) for image load:
  Calimero -d"C:\Users\lpier\Documents\Luca\Pictures" -t3 -m4 -r -D -o3

• Comics time: Use the comic mode to read scanned comic pages from the folder C:\Users[...]Makoma (#1) (remember the old .cbr files?), no automatic timeout (manual change with Ctrl+Alt+N), images sorted by name (-o0), displayed in fit mode (-m4), and launched minimized/iconized (-v):
  Calimero -d"C:\Users\lpier\Documents\Luca\Pictures\2D\Comics\Hellboy\Makoma\Makoma (#1)" -t0 -m4 -o0 -v

• Grab it!: On a multi-monitor setup, load the content of url.txt to download images from the internet using the free Picsum service, change every 5-minutes (-t5), display in alternate mode (-m8) rotating through the monitors in sequence and use the FreeImageRE library as graphics engine (-lFreeImage):
  Calimero -u"C:\WCHG\url.txt" -t5 -m8 -lFreeImage
  (have a look at the sample url.txt file in the C:\WCHG folder)

• You talking to me?: Load the content of words.txt to print the text specified in the file onto the image before setting it as wallpaper (of course working on a copy, never the original!), with a 5-minute timeout (-t5), displaying in stretch mode (-m1), and using the NexgenIPL library (-lNexgenIPL):
  Calimero -d"C:\Users\lpier\Documents\Luca\Pictures\Wallpapers" -w"C:\WCHG\words.txt" -t5 -m1 -lNexgenIPL
  (have a look at the sample words.txt file in the C:\WCHG)

• HACK-a-smack: Last but not least, give a try to the -H option (specifying a number between 1 and 99, as in -H5 or -H50):
  Calimero -d"C:\Users\lpier\Documents\Luca\Pictures\Wallpapers" -t1 -m4 -H25

NEW! (starting from 4.6.1.0) add the -c option to the command line to quietly check if there is a new version available.

♨️ Does it burn? (did the beta💣bomb?)

This is a Beta release. It might have "real" bugs (like memory exceptions) and/or "logical" bugs (such as weird behavior).

• Crashes: If you see a memory exception, please copy the debug data and send it to me.
• Feedback: For logical bugs, suggestions, rants, etc., feel free to reach out.
  Currently hosted on Sourceforge.

👨‍🍳 Under the Hood / Internals

Conceptually, this project is the evolution of Crawlpaper, a Windows 95 wallpaper manager I developed years ago.

Technically, it's written in C/C++ (mhm..., better to say C with classes, or even better, classy C :) on Windows (cartoons) season 10 using Visual Studio 2022 and much love. It integrates several legacy and modern libraries, restored and adapted for high-performance processing:

• BerkeleyDB, brotli, dav1d, FreeImageRE, ImageMagick, libavif, libheif, libjpeg, libpng, libtiff, libungif, libwebp, libz, NexgenIPL, paintLib, zLib.

Currently only the executable is available. As soon I can check all the code and terminate the beta testing, I'll release all the source files as well. Be kind and help me with the tests so I can put out all the code. Thanks!

🧂 User Manual

• Soon...