[BUG] Oversized image (>2000px) poisons session — text-only follow-ups also blocked

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When an attached image exceeds the 2000px many-image limit, the error blocks every subsequent turn in the session, including plain-text messages with no new attachments (because the offending image is re-sent from history). The only workaround is to abandon the session entirely. Suggested fix: either (a) auto-downscale on attach, (b) drop only the over-limit image from re-submission rather than failing the whole request, or (c) offer a "remove image from history" UI affordance.

-- A simple ask is that Claude should reject such an image being attached.

What Should Happen?

disallow to upload unaccepted image

Error Messages/Logs

An image in the conversation exceeds the dimension limit for many-image requests (2000px). Start a new session with fewer images.

Steps to Reproduce

upload image

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

4.7

Claude Code Version

4.7

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_