WordPress站点（Twenty Seventeen主题）Header图片iPhone端无法显示求助

Hey Sally, let's work through this issue—since your header image meets the theme's recommended specs (2000×1200, 456KB JPG), we can cross off size/dimension problems right away. Here are practical steps to get it displaying on iPhones:

• Regenerate Responsive Image Sizes
  Twenty Seventeen automatically creates scaled-down versions of your header image for different devices. It’s possible the iPhone-specific size failed to generate. Install the Regenerate Thumbnails plugin, then go to Tools > Regenerate Thumbnails and run the process. This will rebuild all required image sizes for your theme.

• Inspect Mobile CSS with Safari Dev Tools
  Connect your iPhone to a Mac, enable Web Inspector in Safari settings (on your iPhone: Settings > Safari > Advanced > Web Inspector), then open your site in Safari on the phone. On your Mac, open Safari’s Developer menu and select your iPhone to inspect the header element. Check:

  • Is the background-image property pointing to the correct image URL?
  • Are there media queries (like @media screen and (max-width: 767px)) hiding the header with display: none or visibility: hidden?

• Verify Image Format & Encoding
  Even if it’s a JPG, some encoding or color modes can cause issues on iOS. Open your image in a tool like Photoshop or GIMP, convert it to RGB color mode (avoid CMYK), then save it as a baseline JPG (not progressive, though progressive usually works, but baseline is more universally compatible). Reupload this version to your media library and update the header.

• Clear Cache & Test in Incognito Mode
  If your site uses a caching plugin (e.g., WP Rocket, W3 Total Cache) or CDN, mobile devices might be serving stale cached content. Clear all site cache, then open your site in iPhone Safari’s incognito mode to bypass local browser cache.

• Double-Check Theme Customizer Settings
  Head to Appearance > Customize > Header Media and confirm there’s no option hiding the header on mobile. While Twenty Seventeen doesn’t hide it by default, some customizations or child theme tweaks might have changed this.

If none of these fix it, sharing your iPhone’s iOS version or a screenshot of the header element from Safari Dev Tools could help narrow things down further.

内容的提问来源于stack exchange，提问作者Sally Gill