New session fails with image dimension error after previous session had many images

Bug Description

After uploading a zip file containing 74 images in one session (which caused that session to become unresponsive), brand new sessions also fail when uploading even a single screenshot.

Steps to Reproduce

1. In Session A, upload a zip file containing ~74 images (design mockups)
2. Session A becomes unresponsive with error: "An image in the conversation exceeds the dimension limit for many-image requests (2000px)"
3. Open a brand new Session B (completely fresh conversation)
4. Send a single screenshot (Mac Retina resolution ~3456×2234)
5. Session B immediately fails with the same error: "An image in the conversation exceeds the dimension limit for many-image requests (2000px)"

Expected Behavior

• A new session should have a clean context with no image history
• A single screenshot should work fine in a fresh session (it worked before the incident with 74 images)
• Previously, screenshots at the same resolution worked without issues

Actual Behavior

• New sessions appear to be affected by image state from previous sessions
• Even one image triggers the dimension limit error in fresh sessions
• The error persists across all new sessions

Environment

• macOS Darwin 25.3.0 (Apple Silicon)
• Display: 3456×2234 Retina + 3840×2160 4K external
• Claude Code CLI

Additional Notes

• There is no way to delete images from a session's context once they are loaded
• The user's workaround request: ability to delete/clear images from previous session context
• Suggested feature: allow users to remove images from conversation history to free up context space