Toby Ord Claims a Photo Carries Only ~42 Bytes of Information, Sparking Debate

On September 7, Oxford philosopher Toby Ord published the essay "Curating the World," arguing from the question "how much information does a photo contain?" to the counterintuitive claim that a photo conveys only about 42 bytes of meaningful information, with an upper bound of roughly 340 bits in subsequent discussion. Redwood researcher Ryan Greenblatt and commenter bubblingcreek pushed back, sparking a public debate over the boundaries of measuring information; Anders Sandberg and others amplified it.

Confirmed

• Ord distinguished two perspectives: a 20-megapixel, 14-bit RAW file is about 35MB even before compression, but pixel data vastly exceeds the meaningful information it carries—most of a photo's content can be deterministically inferred from prior knowledge of the world, which is why it compresses to tens of bytes.
• Ryan Greenblatt objected: allowing "pointing" at the physical universe via time and space is cheating—if text were allowed the same trick, an extremely long sequence generated by environmental randomness could be represented in a few bytes.
• bubblingcreek argued "something is off between creation and curation": every bit in a created object is not a bit of information, since it too can be highly compressed—e.g., via time and place, or a program referencing human culture. His concrete counterexample: photographing a note with four Bitcoin seed words plainly conveys 512 bits in the common-sense sense, exceeding Ord's 340-bit bound.
• Ord replied: choosing between two photos conveys only 1 bit, and in the real world sharing a photo can hardly convey more than about 340 bits. He conceded the mnemonic scenario does convey 512 bits in one sense, but not 512 freely chosen bits—you must first stage the scene (write down the words) before photographing it. He argued "conveying information by photograph" has two distinct meanings that must be disentangled.
• As quantitative support, Ord cited a common order-of-magnitude estimate that humans' deliberate output bandwidth in tasks like typing is about 10 bits per second; if true, this upper-bounds the "amount of choice" expressible in a work of given duration. Using a dancer as example, he distinguished "describing complexity" from "constraining actually controllable trajectories": a dancer's continuous movements require lots of information to describe, but a naive description includes trajectories the dancer cannot physically choose. He noted the essay omitted the creative-art argument for space.

Unconfirmed

• The debate has not converged: whether Ord's "freely chosen bits" defense resolves the 512-bit mnemonic counterexample, and whether pointing at the external world should count toward channel capacity, remain unsettled; the 10 bits/sec estimate is cited only as an order-of-magnitude figure, not a rigorous bound.

Why it matters

• The discussion probes the boundaries of measuring information: file size, entropy compression, and semantically meaningful information are not the same, and Ord's estimate is an extreme case for distinguishing data from information.
• The exchange with Greenblatt and bubblingcreek exposes the crux—whether pointing at the external world counts toward channel capacity—which decides whether the answer is a few bytes or massive data.
• The 10-bits/sec bandwidth and the dancer example generalize the discussion to artistic creation: how to characterize a creator's "amount of choice" information-theoretically matters methodologically for understanding creation versus curation.
• The topic drew attention in AI safety and philosophy circles (e.g., Sandberg's reshare) because it bears on understanding information flow between models and the world.

2026-09-07 ~ 2026-09-07 · 14 related posts

• A photo holds only ~42 bytes of information, argues Toby Ord — tobyordoxford · 2026-09-07
• Toby Ord's new essay asks how much information is really in a photograph — anderssandberg · 2026-09-07
• Toby Ord: a photograph can communicate at most ~340 bits of information — tobyordoxford · 2026-09-07
• [source] Does a photo of Bitcoin seed phrases communicate 512 bits? Scholars debate — bubbling_creek · 2026-09-07
• Toby Ord on the two senses of how many bits a photograph can communicate — tobyordoxford · 2026-09-07
• Toby Ord: a photo can convey 512 bits, but not freely chosen ones — tobyordoxford · 2026-09-07
• A photo can't carry 512 freely chosen bits unless you stage the scene first — bubbling_creek · 2026-09-07
• Creation vs curation: every bit in a created object is far more compactly describable — tobyordoxford · 2026-09-07
• Toby Ord: describing a dancer's motion is easy, but limiting it to choices he could control is hard — tobyordoxford · 2026-09-07
• ~10 bits per second: the human bandwidth estimate that upper-bounds information in any artwork — tobyordoxford · 2026-09-07
• Humans output ~10 bits/s of deliberate choice, Oxford philosopher notes in AI art debate — tobyordoxford · 2026-09-07

3 near-duplicate retellings: tobyordoxford · RyanGreenblatt · tobyordoxford