[BUG] VSCode extension 2.1.100+ downscales pasted images to ~640px thumbnails (regression from 2.1.96)

Description

Starting with VSCode extension version 2.1.100, images pasted into the Claude Code chat are silently downscaled to approximately 640×325 pixels before being sent to the API. In version 2.1.96 and earlier, the same paste workflow preserved the original resolution (e.g., 1999×1027 or 2557×1302).

This is a regression — no user-facing setting exists to control this behavior.

Evidence

I analyzed image dimensions across 60+ conversation transcripts spanning March 17 – April 13, 2026. All sessions used entrypoint: claude-vscode.

| Extension Version | Date Range | Image Dimensions | Example Size |
|---|---|---|---|
| 2.1.90 | Apr 4 | 1621×1313, 1998×740 | 302 KB |
| 2.1.92 | Apr 6–8 | 1999×1025, 1998×1024 | 785 KB |
| 2.1.96 | Apr 8 | 1999×1027, 1998×1027 | 257 KB |
| 2.1.100 | Apr 10+ | 637×327 | 86 KB |
| 2.1.101 | Apr 13 | 635×325, 357×224 | 67 KB |

The user pastes a 2557×1302 screenshot (visible in the VSCode UI as image.png 2557×1302), but the transcript records a 638×325 image. The original is lost.

Impact

• Users who rely on screenshots for bug reports, documentation, or visual QA receive degraded images
• Downstream tools that extract images from transcripts (e.g., for embedding in Azure DevOps work items) can only access the thumbnail
• There is no workaround within the extension — no setting controls image resolution

Steps to Reproduce

1. Open Claude Code in VSCode (extension 2.1.100+)
2. Take a screenshot of any full-screen application (e.g., 2560×1440)
3. Paste the screenshot into the Claude Code chat
4. Observe: the VSCode UI shows the original dimensions (e.g., image.png 2557×1302)
5. Check the conversation transcript (.jsonl file) — the image is stored at ~640px wide

Expected Behavior

Pasted images should be sent at their original resolution (as they were in 2.1.96 and earlier), or at minimum provide a configurable max dimension setting.

Environment

• OS: macOS Darwin 25.4.0 (Apple Silicon)
• VSCode: Current stable
• Extension: anthropic.claude-code 2.1.101 (regression introduced in 2.1.100)
• Working version: 2.1.96 and earlier