TUI: image attachment preview renders as a blank thumbnail

Summary

Image attachments do not render correctly in the OpenCode TUI. The attachment is shown as an almost blank, dark thumbnail with only the [Image 1] label, so its visual content cannot be reviewed in the chat.

Environment

• opencode version: v0.0.0-next-17151
• OS: Fedora Linux 44 (Workstation Edition), kernel 7.1.7-200.fc44.x86_64
• Terminal: herdr
• Shell: zsh 5.9
• Install/channel: next
• GPU: Intel Arc Pro 130T/140T (integrated)
• Active plugins: superpowers@git+https://github.com/obra/superpowers.git

Reproduction

1. Start the OpenCode TUI.
2. Attach an image to a prompt.
3. Send the prompt and inspect the image attachment preview in the chat history.

Expected Behavior

The attachment preview should render the image content in the TUI.

Actual Behavior

The preview renders as an almost empty dark thumbnail and displays only the [Image 1] label. The image content itself is not visible.

Additional Context

The issue was observed in a local workspace while using the next build. A screenshot is available in the associated report context. Reproduction frequency and whether it affects every image have not yet been determined.