OptionaleffortHow much computation the encoder may spend. 'fancy' is the default.
A separate axis from EncodeOptions.quality. Quality says what the output should look
like; this says how hard to work to get there. 'fast' bounds the WebP encoder's 4x4
prediction search to its four whole-block modes, which over six fixtures at 800 wide measured
1.18x to 1.45x faster for between 8.8% smaller and 17.5% larger, never more than 0.05 dB
apart. Flat-color illustrations pay the most, because hard diagonal edges are what the
omitted modes are for.
Formats with nothing to trade ignore it and do the exact thing.
OptionallosslessUse the format's lossless mode where it has one.
OptionalprogressiveWrite a progressive or interlaced stream.
OptionalqualityQuality for a lossy format, 1 through 100.
OptionalstripDrop EXIF and other metadata from the output.
What Image.bytes and its siblings take.