要导出每张图片保持最小长宽，您可以使用Spine的导出功能中的Crop设置。这个设置允许您导出的每张图片仅包含动画的必要部分，而不是使用所有动画中最大的长宽尺寸。这样，每张导出的图片都会根据动画内容自动调整大小，以保持尽可能小的尺寸。

具体操作步骤如下：

1. 打开导出对话框。
2. 选择您想要导出的动画。
3. 在Size部分选择Crop选项。这将确保导出的图片仅包含动画所需的部分，而不是固定的尺寸。
4. 完成其他导出设置后，进行导出。

这种方法可以确保每张导出的图片都是根据动画内容自动调整的最小尺寸，而不是所有动画中最大的尺寸。

bcql What version of Spine are you using? As far as I tested with Spine 4.2.08 (the latest stable version), the maximum size for each animation was automatically detected and exported:

If you have that problem with 4.2.08, please show us your export settings.

bcql Ah, I see what you mean, but this is an expected behavior. The GIF you have framed in red looks like this:

Since the Spineboy falls backward in the animation, the size that fits its entire movement is recognized as the appropriate boundary.

So if you want to export at a specific size, you can either use Crop as recommended by Spinebot, or you can create a clipping attachment in the skeleton and use it to crop the entire skeleton for export.