The corresponding bitmap must be at least 50 x 50 pixels in size, or 2,500 individual pixels.
那么对应于位图的尺寸必须至少有 50 x 50 个像素，也就是 2,500 个像素。
2
Most likely, the actual formats will be decided in the marketplace, much as GIF, JPEG, and PNG became the preferred formats for img elements over contenders like BMP, X-Bitmap, and JPEG 2000.