Method compressImagesForVision

cli/cli_file_processing.go:245–287

compressImagesForVision downscales/re-encodes inline image bytes before they reach a vision model — cutting upload bytes, latency and (above the edge cap) the billed vision tokens. Keyless and pure-Go. Controlled by: CHATCLI_VISION_COMPRESS on|off (default on) CHATCLI_VISION_MAX_EDGE

(images []models.ImageContent)

// URL-only images (no inline bytes) are passed through untouched. The function
// is conservative: imgcompress never inflates a payload and never drops alpha.
func (cli *ChatCLI) compressImagesForVision(images []models.ImageContent) []models.ImageContent {
	if strings.EqualFold(strings.TrimSpace(utils.GetEnvOrDefault("CHATCLI_VISION_COMPRESS", "on")), "off") {
		return images
	}
	opts := imgcompress.DefaultOptions()
	if v := strings.TrimSpace(os.Getenv("CHATCLI_VISION_MAX_EDGE")); v != "" {
		if n, err := strconv.Atoi(v); err == nil && n > 0 {
			opts.MaxEdge = n
		}
	}
	if v := strings.TrimSpace(os.Getenv("CHATCLI_VISION_JPEG_QUALITY")); v != "" {
		if n, err := strconv.Atoi(v); err == nil && n >= 1 && n <= 100 {
			opts.JPEGQuality = n
		}
	}

	totalSaved := 0
	out := make([]models.ImageContent, len(images))
	copy(out, images)
	for i := range out {
		if len(out[i].Data) == 0 {
			continue // URL-only; nothing to recompress
		}
		data, res := imgcompress.Compress(out[i].Data, out[i].MediaType, opts)
		if !res.Changed {
			continue
		}
		out[i].Data = data
		out[i].MediaType = res.OutMediaType
		totalSaved += res.SavedBytes()
		cli.logger.Debug("vision: image recompressed",
			zap.String("file", out[i].FileName),
			zap.Int("orig_bytes", res.OrigBytes), zap.Int("new_bytes", res.NewBytes),
			zap.String("orig_dim", fmt.Sprintf("%dx%d", res.OrigW, res.OrigH)),
			zap.String("new_dim", fmt.Sprintf("%dx%d", res.NewW, res.NewH)),
			zap.String("out_type", res.OutMediaType))
	}
	if totalSaved > 0 {
		cli.logger.Info("vision: image compression saved bytes",
			zap.Int("images", len(out)), zap.Int("bytes_saved", totalSaved))
	}
	return out
}

// imageFileExtensions are the extensions we treat as vision attachments.
var imageFileExtensions = map[string]bool{