Saving a figure as image has some style issues

还没有人认领这个 Issue。

When saving a figure as image while using the dark theme the style poses some problems. The axe ticks and labels remain coloured light grey as stated by the style sheet, but this makes them nearly invisible in the saved image.

I would suggest to either use a non-transparent facecolor (napari theme background) or add specific colouring for savefig to the style sheet: `figure.facecolor : 262930` or `savefig.facecolor : 262930`

Another solution would be to change the colours for the axes, ticks and labels for saving, but as far as I know this can't be achieved through matplotlib without changing the colours of the displayed figure as well.

未指定文件或测试。首先重现保存深色主题图形的过程，并结合主题样式表检查保存为图像的路径。完成的标准是：保存的图像具有清晰可读的坐标轴刻度和标签，同时不会导致所显示图形的样式不正确。

由索引模型根据 Issue 内容生成。