Show HN: Kiln – a fast, native batch image processor

[the-hangry-dev]

I was tired of outdated UIs and performance of similar tools. Nor did I want to write ImageMagick scripts every time I needed to resize/convert/watermark a folder with a few thousand images.

It's a native desktop app built with C++23, Skia for rendering, libvips for image processing and my own cross-platform UI toolkit - no Electron/Qt.

It allows building reusable pipelines: resize, convert, compress, watermark, sharpen, blur, rotate, flip, rename, and metadata (EXIF/IPTC/XMP) editing, chained in any order and saved for reuse. Batches run in parallel.

Everything is local — no uploads, no signups/account, no telemetry, no network calls during processing.

It's currently in public beta (as mentioned, no signups or accounts needed - can just download), for Windows and Linux (Wayland only). Waiting for the Apple certificate to sign the macOS dmg installer, at which point I'll post the download link for macOS.

Business model: free beta now, one I've received enough feedback and the tool is mature enough - a one-time license per major version once it's out of beta. There won't be any subscriptions or telemetry ever.

Would love to get your feedback, especially on missing formats/operations (e.g. RAW file formats, watch folders, a CLI) to drive the roadmap to the first official version.

Cheers.

[jcupitt]

Hello, looks nice! I had a few thoughts:

- I'd consider adding support for libvips smartcrop, ICC colour management, HDR, image alpha

- can you join pipelines? you could have one making a background, one making a foreground, then composite them, for example

- your benchmarks don't measure peak memory use, it can be a useful thing to test, especially if people are processing large images (eg. the output of every modern smartphone sigh)

- have you benchmarked against nip4, the official libvips GUI? it has a CLI mode you can run with GNU parallel

- I agree, a CLI mode for your tool sounds useful

[the-hangry-dev]

Hi, thanks for the comments.

- I'd consider adding support for libvips smartcrop, ICC colour management, HDR, image alpha Fair enough - I wanted to first see if there's interest in the tool and then I'd definitely add more functions.

- can you join pipelines? you could have one making a background, one making a foreground, then composite them, for example No, you can't join them currently in this way. Sounds like an interesting advanced feature to add.

- your benchmarks don't measure peak memory use, it can be a useful thing to test, especially if people are processing large images (eg. the output of every modern smartphone sigh) Very good point, I should definitely have measured that too. Will add that soon.

- have you benchmarked against nip4, the official libvips GUI? it has a CLI mode you can run with GNU parallel I haven't and that would indeed by interesting to measure. Will look into it as well.

- I agree, a CLI mode for your tool sounds useful I'll probably add a CLI if the tool gets traction and it's requested.