I'm attempting to create a sharepoint page programatically by adding an image gallery web part. How do I access the properties of that web part? I don't see the documentation anywhere for Image Gallery like I do for the Image web part. Custom Properties for Image Web Part
if you go to the hosted workbench (_layouts/15/workbench.aspx) and configure the canvas how you want, select the "Web Part Data" button on the top left. That will pop up a window with the serialization format for both modern and classic. The value in the "Modern Pages" tab is the value that should be stored in the canvas field.