Claude Code's Read Tool Silently Downscales Images, Causing Hallucinations

A Reddit user reports that Claude Code's read tool silently downscales images before passing them to the model. When the user sent 4.7 retina screenshots to Claude Opus 4.7 via Claude Code and asked it to extract text from them, the model returned a vague summary saying it "couldn't fully read every value." The text was clearly readable on the user's monitor at full resolution.

Upon investigation, the user discovered that the read tool downscales images before the model processes them. The model sees a degraded copy, not the original screenshot. The tool returns results that are indistinguishable from reading a text file — no warning is given that the image has been resampled. This means developers relying on Claude Code to extract UI text, error messages, or other on-screen content from screenshots may be getting confident but inaccurate answers based on blurry inputs.

The user expressed concern that many previous screenshot-based interactions may have produced hallucinations as a result. The post has generated significant discussion in the r/ClaudeAI community.