Pick the page codec: WebP, PNG or mozjpeg
Every converted page is saved as a JPEG today, at a quality you can set. JPEG is the safe choice because every reader opens it, but it is not always the best one. WebP makes a smaller file at the same quality on readers that support it, PNG keeps flat greyscale linework perfectly clean at 4 or 8 bits, PNG for colour pages only keeps the few colour pages lossless while the rest stay small, and mozjpeg squeezes a JPEG a little smaller than the standard encoder. The planned codec control lets you choose. We are being straight with you: it is not live yet, so this page does not offer it.
What works today: JPEG output with a quality slider from the default of 85 up to 95, and lossless repacking when you want the original images untouched. The engine underneath already takes every codec on this page; what is planned is the control and a note about which readers open what.
The codec control is coming soon
This control is planned, not live yet. Use the JPEG quality slider in the meantime.
Vote for this on the roadmapWhat the codec control will do
WebP for modern readers
Lossy WebP at a comparable quality is roughly a quarter smaller than JPEG. Kobo and most Android readers open it; older Kindles do not, so the control warns per device.
PNG at 4 or 8 bits
Greyscale manga pages quantised to 16 or 256 greys, with dithering on or off, come out crisp with no JPEG blocking around the lettering.
PNG for colour pages only
A volume with a handful of colour pages keeps those lossless and leaves the grey pages as small JPEGs, so the file does not balloon for the sake of ten pages.
mozjpeg, and the quality slider today
mozjpeg produces a smaller JPEG at the same visible quality. Until the control ships, the JPEG quality slider on the quality page is the live way to trade size for sharpness.
Honesty first
A WebP option that produced a file an old Kindle cannot open would be a trap. The control ships with a per-device check, not before.
The live converter helps now
The JPEG quality slider, the target size option and lossless repacking are all live today, and the quality page presets 95 for the sharpest JPEG the engine allows.
Frequently asked questions
Can I output WebP or PNG pages right now?
Not yet, and we will not pretend otherwise. Pages are JPEG today with a quality slider, and lossless repacking keeps the originals when they are already PNG.
Which readers open WebP?
Kobo readers and most Android reading apps do. Kindles before the 2024 models do not reliably, which is why the planned control checks the device profile before offering it.
Is PNG not much larger than JPEG?
For photographs, yes. For greyscale linework quantised to 4 bits it is often smaller than a high quality JPEG, with no compression artefacts around the text.
Will you announce when it is ready?
Yes. When the control ships it appears in the output options and this page hosts it. You can vote for it on the roadmap in the meantime.
MangaConverter runs on Kindle Comic Converter (KCC), the open-source engine, whose WebP, PNG and mozjpeg options already travel with every job. The studio control for them is planned, and this page will host it once it works.