ImageResize is a simple plugin for creating small copies of an image when it is uploaded by standard media manager and Drag&Drop in editor. Only width available.
Install the plugin.
Go to Extensions -> plugin, find Image Resize and setup.
All what you need to do - is install and configure just as you like. The ImageResize will do everything itself.
There are four different versions of images you can configure: small, medium, medium-large and large.
You can create all thumbnails together or create only what you need.
You can even just disable the creation of thumbnails when downloading and enable only Drag&Drop.
Supports the processing and insertion of images into the editor with the Drag&Drop, creates resized image and place in editor instead fullsize.
git clone https://github.com/geqo/JoomlaImageResize.git
Don't forget about composer update in plugin directory if you use git clone.
https://geqo.space/joomla/plg_content_imageresize/updates/latest/plg_content_imageresize.zip
PHP 5.6
Joomla 3.8
For Joomla 3.6 select Joomla3.6 branch. Or download latest from
https://geqo.space/joomla/plg_content_imageresize/Joomla3.6/latest/plg_content_imageresize.zip
23 August 2018, 1.1.2 - forgot about image/jpeg type :) Fixed.
22 August 2018, 1.2.1 - added developer messages.
29 August 2018, 1.3.0 - added default 10% compression for JPG, sure if it enabled.
11 October 2018, 1.4.1 - added PNG to JPG conversion
30 October 2019, 1.4.2 - critical fix, image cannot be processed if filetype is JPEG