immich/web/src/lib/utils/thumbnail-util.ts

/**
 * Calculate thumbnail size based on number of assets and viewport width
 * @param assetCount Number of assets in the view
 * @param viewWidth viewport width
 * @returns thumbnail size
 */
export function getThumbnailSize(assetCount: number, viewWidth: number): number {
  if (assetCount < 6) {
    return Math.min(320, Math.floor(viewWidth / assetCount - assetCount));
  } else {
    if (viewWidth > 600) return viewWidth / 7 - 7;
    else if (viewWidth > 400) return viewWidth / 4 - 6;
    else if (viewWidth > 300) return viewWidth / 2 - 6;
    else if (viewWidth > 200) return viewWidth / 2 - 6;
    else if (viewWidth > 100) return viewWidth / 1 - 6;
  }

  return 300;
}