扁平化渐变风图片加速闪电图标矢量元素

minimalist flat vector app logo for "千图AI", an AI creative image platform. A single geometric icon: a stylized picture frame combined with a subtle AI spark / lightning bolt inside, clean gradient fill from deep purple #7C3AED to sky blue #38BDF8, pure white background, centered mark only, no text, no shadow, no gradients outside the shape, sharp vector edges, modern tech aesthetic, suitable for a browser OAuth login page header, 512x512