IconVault's Sprite Sheet Generator merges your individual images into a single PNG sprite sheet and writes the matching CSS classes for you, one class per sprite with correct width, height and background-position. Each uploaded file becomes one sprite, named after the file, so your classes come out readable like `.sprite-logo`.

Choose a grid layout (auto or fixed columns) or packed rows for mixed sizes, add padding between sprites, and enable Retina 2x to get both 1x and 2x sheets in a ZIP with CSS sized for standard displays. Everything runs locally in your browser: files never leave your device. Free with a daily trial, unlimited with Pro.