1. Mass changes to graphs. You can copy formatting between sheets [Format at the Worksheet Level]
After you format a worksheet, you can copy its formatting settings and paste them into other worksheets. The settings that you can copy are anything you can set in the Format pane, with the exception of reference lines and annotations. Adjustments like manual sizing and level of zoom are not copied.
To copy and paste formatting between worksheets:
- Select the worksheet from which you want to copy formatting.
- Right-click (control-click on Mac) the worksheet tab and select Copy Formatting.
- Select the worksheet you want to paste the formatting into.
- Right-click (control-click on Mac) the worksheet tab and select Paste Formatting.
2. Exporting graphs in a standardized way. Regarding this, I'm not sure if an option exists to export all images as a batch. But you can print the whole book as a pdf and configure the layout of the printing. Also you can export each sheet as an image file. [Export Views]
One solution might be to put all the grahps in a dashboard as you want it to be (standard measures) and then export that view to a pdf or image file.
Hope you find it useful!