下列何者是建立高成效圖片素材資源的最佳做法？

Uploading at least four relevant and unique images per ad campaign or ad group is a best practice because it provides the advertising platform with sufficient variety to test and optimize performance across different placements and audiences. This diversity allows the system to identify which images resonate best, leading to higher engagement and conversion rates. Providing only square images limits flexibility and reach, as other aspect ratios (like landscape or portrait) are often required or perform better in specific ad placements. Choosing images with a plain white background is not universally effective; the best background depends on the product, brand, and target audience. While important content should be prominent, mandating it occupy exactly 50% of the image and be perfectly centered is an overly rigid rule that doesn't account for diverse creative strategies or optimal visual hierarchy.