[BUG] CLI session halted after API Error 400 invalid_request_error using 870KB PNG

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 I drag a PNG file from my desktop on macOS into the terminal where Claude Code is running, I get an API error that halts further work. The same error appears with all subsequent prompts. I am running this within VS Code. In order to proceed, I must start a new Claude Code session.

• Version: 2.1.20
• Platform: macOS (Darwin 25.2.0)
• Environment: VS Code integration
• Image: 870KB PNG (screenshot from macOS)
• Error: API Error 400 - "Could not

process image"

• Impact: Session became unusable, had to

start new session

• Request ID: req_011CXYi24Fjrr69V6R1tsA4k

What Should Happen?

I should be able to drag and drop screenshots that are saved as PNG into the terminal to provide context. If something legitimate is preventing it from being loaded, I should be able to skip loading it and continue my conversation without having to start a new Claude Code instance.

Error Messages/Logs

screenshot                                
  ⎿  [Image #2]                             
  ⎿ API Error: 400                          
    {"type":"error","error":{"type":"invalid
    _request_error","message":"Could not    
    process image"},"request_id":"req_011CXY
    huLP9oKNxc5eqWibbk"}

Steps to Reproduce

1. run claude code in the terminal from within VS Code
2. take a screenshot of an app from my computer. Doesn't matter what it is of. This happens every time.
3. go to my desktop on macOS and find the file. Confirm the format is PNG and size in this case is 870KB.
4. drag the file from the desktop folder in Finder and release it in the Claude Code terminal.

Error is shown and I cannot get around it without starting a new session.

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

It's been broken for several months-- not sure which version it was last working on. Whatever was current in Oct. timeframe I think.

Claude Code Version

Claude Code CLI v2.1.20

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_