Your files stay on your Mac.
BMP stores every pixel uncompressed, producing large files with no quality tradeoff. AVIF uses modern compression to deliver sharp images at a fraction of the size — you control exactly how much quality to trade for smaller files. Convertessa runs the conversion on your Mac; your images never leave the machine.
Drag one BMP image or an entire folder into Convertessa. Batch mode processes every .bmp file in one pass, no manual queuing required.
Pick AVIF from the output list, then set the quality slider to balance file size against visual fidelity — Convertessa never pre-selects a quality level for you.
Click Convert. Convertessa writes AVIF files alongside the originals — resolution preserved, EXIF stripped, no upload required.
Images, audio, video, documents, archives and eBooks — all converted natively, right on your Mac.
Pick a format you have — see everything Convertessa can turn it into.
Convert hundreds of files at once with per-type group defaults and individual overrides.
First-class support for HEIC, AVIF and WebP — encode and decode, both ways. Read JPEG XL and a dozen more modern formats too.
Drop files anywhere on the window. Native, instant, and exactly what you’d expect on a Mac.
Dial in compression, resolution and bitrate. Keep originals pristine or shrink for sharing.
Never overwrite a file by accident. Convertessa appends safe suffixes automatically.
Every job is logged locally. Re-run a previous conversion or revisit recent outputs in a click.
Bundle your converted files straight into a single ZIP, TAR or 7z — packaged and ready to share the moment a job finishes.
Right-click any file in Finder and choose Convert. A Quick Action handles it on the spot — no need to open the app first.
Shrink Convertessa to a tidy mini window that tucks into a corner — just a drop zone and a format picker for quick, one-off conversions.
No cloud. No account. No upload. Every conversion happens entirely on-device, using the power already in your Mac. What you convert is nobody’s business but yours.
Script conversions, wire them into your build, or batch a folder from the terminal. The same engine, no GUI required.
Read the full CLI documentation →Shrink Convertessa down to a small, focused window — drop, convert, done, with your recent conversions one click away.
macOS 14+ · Apple Silicon & Intel
New formats, new features, and fixes — every release, on the record.
Use the quality setting before converting. Lower quality produces smaller files; higher quality preserves more detail. Because AVIF is a lossy format, you decide the tradeoff — Convertessa never picks it for you.
No. Convertessa runs entirely on your Mac. BMP files are read and written locally; nothing is sent to a server or cloud service.
Yes. Drop a folder onto Convertessa or pass a directory path to the CLI: convertessa ./folder/ --to avif. Every BMP file in the folder is converted in one batch.