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Thomas Bachem
c5757770b0
`--screenshotFormat` says JPEG and WebP "helps reduce context size in AI conversations". The byte saving is real, but it does not reach the context: image tokens scale with the image's dimensions, not with the size of the encoded payload. Token delta on each Claude turn that followed exactly one image, with the surrounding text small enough that the image dominates it, grouped by pixel count so only the format differs: | pixels | format | n | median bytes | median tokens | | --- | --- | ---: | ---: | ---: | | 1.5-1.8 MP | jpeg | 115 | 326 KB | 2362 | | 1.5-1.8 MP | png | 298 | 357 KB | 2361 | | 2.5-2.8 MP | jpeg | 45 | 444 KB | 3574 | | 2.5-2.8 MP | png | 24 | 252 KB | 3604 | Same pixels, same cost. Each delta carries a small fixed per-turn overhead, so read the pairs against each other rather than as absolute image cost. The formats come from separate captures rather than one image encoded twice, so the byte column shows only that cost ignores it – in the second pair the larger files are the cheaper ones. The numbers are [Claude](https://platform.claude.com/docs/en/build-with-claude/vision)'s, but [GPT](https://developers.openai.com/api/docs/guides/images-vision) and [Gemini](https://ai.google.dev/gemini-api/docs/tokens) price images the same way, by pixel dimensions in patches or tiles. Neither charges on encoded bytes. `--screenshotMaxWidth` just below promises the same thing and does deliver, since it changes the dimensions. New wording: > Override the default output format used by take_screenshot when the caller does not specify one. JPEG and WebP are ~3-5x smaller than PNG, which reduces transfer and storage size. To reduce context size use --screenshotMaxWidth / --screenshotMaxHeight, since image tokens scale with dimensions rather than encoded bytes. Unset preserves the existing default ("png"). `docs/configuration.md` is generated from that description and updated to match.