SrcSet Responsive Images for WordPress

FAQ

What are SrcSet groups?

SrcSet groups allow you to change the dimensions of images based on the current width of the user’s browser. When you assign a SrcSet group to an image size within WordPress (e.g. medium or large). Any image within a post or page using that image size will have the SrcSet group’s attribute applied to it.

For example, this ‘medium’ image…

img class=”alignnone size-medium wp-image-1264″ src=”http://www.domain.com/wp-content/uploads/2011/05/test_img-200×150.jpeg” alt=”test_img” width=”200″ height=”150″

Would change to something like this…

img class=”alignnone size-medium wp-image-1264″
src=”http://www.domain.com/wp-content/uploads/2011/05/test_img-200×150.jpeg”
srcset=”http://www.domain.com/wp-content/uploads/2011/05/test_img-125×125.jpeg 640w,
http://www.domain.com/wp-content/uploads/2011/05/test_img-200×150.jpeg 1024w,
http://www.domain.com/wp-content/uploads/2011/05/test_img.jpeg 1440w,
http://www.domain.com/wp-content/uploads/2011/05/test_img-1440×1200.jpeg 1506w”
alt=”test_img” width=”200″ height=”150″

Note that the ‘srcset’ attribute had been added to the img tag and will instruct the browser to replace the image with different sizes at these breakpoints, 640w, 1024w, 1440w, and 1506w.

I’ve set up an SrcSet group for an image size, but my images are not receiving the srcset attribute. What’s wrong?

If the images were already uploaded to the Media Library, you may have to regenerate thumbnails. We recommend using Regenerate Thumbnails for this.

How do I uninstall and remove the srcset attributes from my images?

1. Go to Tools > SrcSet Settings
2. Click “Regeneration” tab on the left of options page
3. Select “Uninstall srcset” from dropdown option
4. !!Warning!! Backup your database BEFORE this step as the process is irreversible!! Click the ‘Regenerate srcset’ button
5. You can now uninstall the plugin

What are Image Groups?

SrcSet Groups give you a way to relate breakpoints to any specific image size (for example, medium). You can set specific breakpoints that align to your theme, and load in smaller versions of the same image. You can select existing image sizes (thunbmail, medium, large), custom image sizes created by themes or plugins, or add a custom image size with dimensions you create.

Note: If you use the Custom image size, remember to regenerate your thumbnails, otherwise these images will not exist, and therefore not be used within the srcset attribute.

I just installed this plugin, but I have existing content with images that I’d like to add srcset attributes to. Can I do this?

Absolutely! In the srcset Settings area, there is a Regeneration page. This feature will go through all public posts (pages and posts by default), and regenerate the image tags of WordPress attachments in post content.

I just installed a new theme, and the breakpoints I created for my SrcSet groups no longer align with my theme. What can I do?

First, take some time and adjust your SrcSet groups and their breakpoints. Once everything is set up properly to your liking, use Regenerate Thumbnails to create any new image sizes you’ve created. Then use the Srcset Regeneration tool.

What about Retina support for srcset?

We intended on including the pixel density (x) support into the plugin. On further investigation, we realized it was not nearly as useful as the breakpoint (w) feature.

In future releases, we will be adding in the pixel density (x) feature support, and hope that it will become a more useful feature, to be combined with the breakpoint (w) feature.

What benefits does this plugin give to my website?

The srcset attribute is a new HTML5 spec which allows us to specify multiple versions of the same image for various screen sizes. This means that you can serve smaller images for smaller screens and devices, which means your viewers will load your page much faster.

Need help setting up a SrcSet Group?

In the plugin options under Tools > SrcSet Settings, click the ‘Help’ tab on the left and following the instructions for more examples.