reference-example

Reference: `imageproc` CLI

> Doc type: **reference**. Exhaustive and consistent; optimized for scanning and `Ctrl-F`, not for > reading top to bottom. Every entry uses the same structure. For a guided walkthrough, see the tutorial.

Synopsis

imageproc <command> [options] <input> [output]

Commands

| Command | Purpose | |---|---| | `resize` | Scale an image to a target width/height | | `convert` | Change file format | | `optimize` | Re-encode to reduce file size |

Global options

Every entry below follows the same shape: **flag**, type, default, description, example.

`--quality`

• **Type:** integer (1–100)
• **Default:** `82`
• **Description:** Output encoder quality. Higher is larger and sharper. Ignored for lossless formats.
• **Example:** `imageproc optimize --quality 70 photo.jpg`

`--width`

• **Type:** integer (pixels)
• **Default:** *(unset — preserves source width)*
• **Description:** Target width. If `--height` is omitted, aspect ratio is preserved.
• **Example:** `imageproc resize --width 1200 hero.png hero@2x.png`

`--height`

• **Type:** integer (pixels)
• **Default:** *(unset — preserves source height)*
• **Description:** Target height. Combine with `--width` to force exact dimensions (may distort).
• **Example:** `imageproc resize --width 800 --height 600 in.jpg out.jpg`

`--format`

• **Type:** enum (`jpeg` \| `png` \| `webp` \| `avif`)
• **Default:** *(inferred from output extension)*
• **Description:** Output format. Overrides the extension when both are given.
• **Example:** `imageproc convert --format webp in.png out.webp`

`--overwrite`

• **Type:** boolean flag
• **Default:** `false`
• **Description:** Allow writing over an existing output file. Without it, an existing target aborts the run.
• **Example:** `imageproc optimize --overwrite big.jpg`

Exit codes

| Code | Meaning | |---|---| | `0` | Success | | `1` | Invalid arguments | | `2` | Input file not found or unreadable | | `3` | Output exists and `--overwrite` not set | | `4` | Encode/decode failure |

Environment variables

| Variable | Default | Effect | |---|---|---| | `IMAGEPROC_THREADS` | number of CPUs | Worker threads used for encoding | | `IMAGEPROC_TMPDIR` | system temp | Scratch directory for intermediate files |

---

Why this is a good reference: identical structure for every flag, a default stated for each, tables for enumerable facts (exit codes, env vars), and no narrative. A reader lands via search, reads one entry, and leaves.