WordPress 4.9.4移动端图片过宽：srcset属性未触发缩放问题咨询

Hey there, let's work through this mobile image sizing problem you're facing. I've dealt with similar quirks on older WordPress versions before, so here are some practical steps to get those images scaling correctly:

• Check your theme's responsive CSS
  A lot of themes from the 4.9.x era might be missing the basic styles that force images to fit mobile screens. Head to your theme's style.css file (via Appearance → Editor) and look for rules targeting img or .entry-content img. Make sure they include these lines:

  img {
    max-width: 100%;
    height: auto;
  }
  

  Double-check any mobile-specific media queries too—sometimes themes accidentally override this with fixed widths or !important declarations that break responsiveness.

• Verify your srcset configuration
  Even though you see the srcset attribute, it might not be set up correctly for your mobile viewports. Go to Settings → Media and confirm your default image sizes (Thumbnail, Medium, Large) are defined properly. WordPress uses these to generate the srcset variants; if none of them are small enough for mobile, the browser will just load the original full-size image. You can also use Chrome's DevTools (toggle the device toolbar) to inspect the image element and see which srcset variant the browser is actually loading.

• Rule out plugin conflicts
  Old plugins (especially image optimization or caching tools) can mess with srcset functionality in WordPress 4.9.4. Try temporarily disabling all plugins, then reload your mobile page. If the images start scaling correctly, re-enable plugins one by one to find the culprit. You can either update that plugin (if a compatible version exists) or swap it out for an alternative that works with your WP version.

• Quick manual fix for individual images
  If you need a temporary solution while troubleshooting, edit your posts, select the problematic image, and use the "Edit Image" option to set its alignment to "Center" or "Full Width" (if your theme supports it). Alternatively, add a custom class like responsive-img to the image and add this to your style.css:

  .responsive-img {
    max-width: 100%;
    height: auto;
    display: block;
    margin: 0 auto;
  }
  

内容的提问来源于stack exchange，提问作者Captain_Planet