Best image size for a Codex theme

Choose resolution, aspect ratio, composition, and format that survive desktop crops without wasting bytes.

Edited and reviewed by CodexTheme Tools editorial. Reviewed July 29, 2026. Status: Published.

Sources: Reviewed against the current upstream Codex theme sources and Codex desktop behavior cited in this guide. No site-owned macOS or Windows device verification is claimed unless a published runtime receipt exists.

Platform behavior can change. Compare this guide with the Codex Dream Skin repository at commit 611c10176a27.

01Start with a wide high-resolution source

02Place the focal point away from controls

03Preview fit and fill

04Export WebP or PNG at a known size

Use 16:9 as a practical working canvas

The Builder exports 1920×1080 and 2560×1440 because both are predictable widescreen targets. A source at least 2000 pixels wide provides enough detail for common desktop windows. Very tall images can work, but Fill will crop aggressively and Fit may expose background tint at the sides.

Composition matters more than raw resolution

Keep the left side and lower center quieter because navigation and the composer often occupy those areas. Move a strong face, logo-like mark, or bright light away from text. Zoom and position should create useful negative space rather than merely preserve every source-image edge.

Choose WebP or PNG intentionally

WebP at high quality is the default for photographic or gradient artwork and usually saves substantial bytes. PNG is useful for crisp flat art, grids, or assets that must remain lossless. Avoid converting a small, already-compressed JPEG to a huge PNG; it increases size without restoring detail.

Never use a workspace screenshot as a wallpaper if it contains private conversations, file paths, email addresses, or credentials.

Completion checklist

Source is at least 2000 px wide
16:9 crop is intentional
Composer area stays calm
Export format matches artwork

Use 16:9 as a practical working canvas

Composition matters more than raw resolution

Choose WebP or PNG intentionally

Completion checklist

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