🔧 Image Expand Batch

重点说明expand的逻辑，源码如下：

if size < orig_size:  # 缩减
    scale = (orig_size - 1) / (size - 1)
    for i in range(size):
        out[i] = image[min(round(i * scale), orig_size - 1)]

else:  # 扩展
    scale = orig_size / size
    for i in range(size):
        out[i] = image[min(math.floor((i + 0.5) * scale), orig_size - 1)]

举例：扩展原始3图，目标7图

orig_size = 3
size = 7
scale = orig_size / size = 3 / 7 ≈ 0.4286
i=0 → floor((0+0.5)*0.4286)=floor(0.214)=0
i=1 → floor((1+0.5)*0.4286)=floor(0.642)=0
i=2 → floor((2+0.5)*0.4286)=floor(1.071)=1
i=3 → floor((3+0.5)*0.4286)=floor(1.5)=1
i=4 → floor((4+0.5)*0.4286)=floor(1.928)=1
i=5 → floor((5+0.5)*0.4286)=floor(2.357)=2
i=6 → floor((6+0.5)*0.4286)=floor(2.785)=2