您可以使用fs模块和window.postMessage函数

const { ipcMain } = require('electron')

// Listen for a message from the renderer process
ipcMain.on('load-local-image', (event, arg) => {
  // Read the contents of the local file using the fs module
  const fs = require('fs')
  const imageData = fs.readFileSync('/path/to/local/image.jpg')

  // Send the image data back to the renderer process
  event.sender.send('local-image-loaded', imageData)
})

const { ipcRenderer } = require('electron')

// Send a message to the main process to load the local image
ipcRenderer.send('load-local-image')

// Listen for a response
ipcRenderer.on('local-image-loaded', (event, imageData) => {
  // set the background image
  // document.body.style.backgroundImage = `url(${imageData})` with url
  document.body.style.backgroundImage = `${imageData}`
})

在文档中阅读有关preload.js的更多信息：https://www.electronjs.org/docs/api/web-preferences#preload。