Imsanity

Activating Imsanity will not alter any existing images. Imsanity resizes images as they are uploaded so it does not affect existing images unless you specifically use the "Bulk Image Resize" feature on the Imsanity settings page. The Bulk Resize feature allows you to quickly resize existing images.

WordPress uses the GD library to handle the image manipulation. GD can be installed and configured to support various types of images. If GD is not configured to handle a particular image type then you will get this message when you try to upload it. For more info see http://php.net/manual/en/image.installation.php

You can re-name your file and add "-noresize" to the filename. For example if your file is named "photo.jpg" you can rename it "photo-noresize.jpg" and Imsanity will ignore it, allowing you to upload the full-sized image. If you are a developer (or have one handy), you can also use the 'imsanity_skip_image' filter to bypass resizing for any image.

While Imsanity does compress JPG images in the process of resizing them, it uses the standard WordPress compression. Thus, the resulting images are not efficiently encoded and can be optimized further (without quality loss) by the EWWW Image Optimizer and many other image optimization plugins.

If the images can be found in the Media Library of your site, then it is likely Imsanity will resize them. Imsanity uses the wp_handle_upload hook to process new uploads and can resize any existing images in the Media Library using the Bulk Resizer. If the images are not in the Media Library, you can use the EWWW Image Optimizer to resize them.

Photos taken on any modern camera and most cellphones are too large to display full-size in a browser. This wastes space on your web server, and wastes bandwidth for your visitors to view these files. Imsanity allows you to set a sanity limit so that all uploaded images will be constrained to a reasonable size which is still more than large enough for the needs of a typical website. Imsanity hooks into WordPress immediately after the image upload, but before WordPress processing occurs. So WordPress behaves exactly the same in all ways, except it will be as if the contributor had scaled their image to a reasonable size before uploading. The size limit that imsanity uses is configurable. The default value is large enough to fill the average vistor's entire screen without scaling so it is still more than large enough for typical usage.

You might not want to use Imsanity if you use WordPress as a stock art download site, to provide hi-resolution images for print or use WordPress as a hi-resolution photo storage archive.

When an image is uploaded WordPress keeps the original and, depending on the size of the original, will create up to 4 smaller sized copies of the file (Large, Medium-Large, Medium, Thumbnail) which are intended for embedding on your pages. Unless you have special photographic needs, the original usually sits there unused, but taking up disk quota.

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.

Questions may be posted on the support forum at https://wordpress.org/support/plugin/imsanity but if you don't get an answer, please use https://ewww.io/contact-us/.