How to optimize images for mobile speed with free Imsanity plugin.

WordPress Mobile Speed


There are no affiliate links on PagePipe.

The Imsanity plugin is one of our secret weapons for image optimization on client sites. As we researched this plugin, we found that it was authored by the same company publishing the EWWW Image Optimizer. The other plugin we love for cleaning up a poorly optimized image media library is PNG to JPG plugin. Both these plugins allow retroactive reprocessing of media library images for speed.


Sadly, those aren’t typos on the plugin spellings: Imsanity (300,000 active installs) and EWWW (700,000 active installs). We think both these plugins are poorly named. In spite of that marketing error, they’ve been discovered and accepted.

[dropcap]E[/dropcap]WWW Image Optimizer, a paid subscription service (API), also authored Imsanity plugin. That was in collaboration with Jason, a software developer, in Chicago, IL. For example: 3,000 EWWW compressed images cost about 9 dollars – their smallest order size. You pay in advance with prepaid credits.

We don’t like services or plugins that cost repeat annual or usage fees. We call that *rent*.

The geographical location is in Glendive, Montana. Population: 5,107. It’s the home to Dawson Community College. The Imsanity and EWWW plugin author is Shane Bishop. He works at the college as Director of Technology.

Imsanity is a free plugin. (200,000+ active installs, 154k package size). It isn’t the same as EWWW plugin. For EWWW, remote mage processing happens on another server. For Imsanity, processing is on your host server using WordPress features. Default JPEG quality is 82 to match the WordPress default. This has been proven to be the equivalent of a Photoshop compression quality setting of 50. Images with this setting pass the criteria for speed optimization.

WordPress has automatic image optimization features. But not for original images, only resized images. If it optimized images upon upload, no optimization plugin would be needed.

Imsanity is an automation plugin to resize images in your WordPress media library. It can adjust the dimensions if they are larger than width and height settings. That is a unique feature. Optimization plugins like free Smush (1 million+ active installs) do not resize images. They only change the compression.  And it isn’t lossy compression. It’s lossless. That sounds like a good thing but it’s not. It only compresses images by about 10 percent. Whereas, visually-lossless or lossy compression reduces image weight by 70 percent. Smush is the worst choice for speed.

Activating Imsanity plugin doesn’t alter existing archived images. Imsanity only resizes images when uploaded. But you can retrofit with a “Bulk Image Resize” feature in the Imsanity settings. The “Bulk Image Resize” feature allows you to resize all existing images in the media library.

Imsanity doesn’t search your file system to find large files. Instead it looks at the “metadata” in the WordPress media library database. To override this behavior, enable deep scanning in the plugin settings. Then it will scan the server.

You can re-name your original image file and add “-noresize” to the filename. For a file name of “photo.jpg,” you can rename it “photo-noresize.jpg.” Then Imsanity will ignore it, allowing you to upload the unchanged full-sized image. That will protect an image if needed.

Photos from modern cameras and cellphones are too large for full-size browser display. DSLR camera photos are for high-quality printing. They’re over-sized for web page display. They turn your site into a slug for speed.

Imsanity allows you to set a *sane* limit. That constrains all uploaded images to a reasonable size. They will still be large enough for typical website needs.

Imsanity changes happen immediately upon image upload, but before WordPress processing occurs. WordPress behaves exactly the same as always. If a contributor uploads oversized images, Imsanity scales it and replace the original.

Imsanity uses a configurable size limit. The default value is large enough to fill a typical web screen without scaling.

Don’t use Imsanity for the following:

  • Stock art download sites.
  • Providing high-resolution print images.
  • Storing a high-resolution photo archive.

WordPress onboard image processing – without plugin assistance – includes poor features for resource consumption.

During upload WordPress keeps the original full-size image in the media library. Depending on the original size, WordPress creates up to 4 smaller-sized file copies:

  • Large
  • Medium-Large
  • Medium
  • Thumbnail

These are for embedding on your pages and posts. The original usually sits on the server unused, taking up server disk space. That usually isn’t a big issue. But we’ve seen exceptions. These can make website backup with normal plugin methods impossible if your media library grows too large to handle.

Imsanity is short for “Image Sanity Limit”. A sanity limit is a term for limiting something down to a size or value that is reasonable.



Steve Teare
performance engineer
May 2022


PagePipe Site Tuning Services for Speed

Instead of band-aid approaches, we drill down to the root cause of your slow site. This is origin optimization. Also known as site tuning. To do this, we analyze site components:

  • Hosting
  • Theme
  • Plugins
  • Scripts and third-party services.
  • Images and media library.
  • We minimize globally loading plugin effects.

Find out more details about Site TuningGet Speed!