循环的下一部分控制像素坐标的设置，条件是当前时间帧在起始帧之后。

The next loop section controls setting pixels coordinates only if the frame at that position is greater than the start frame.

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图像的高度和宽度的最大值被设置为 150 像素，但是保持高宽比例不变，因此图像没有变形。

The height and width are maxed out at 150 pixels, but the ratio of the height-to-width is preserved so the images are not distorted.

youdao

对于id列将宽度设置为50(像素)。

Set the width to 50 (pixels) for the id column.

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