Multiple Images Method 1: Go to media section and make sure you’re on the list view. Select the images you want to regenerate, then go to the drop-down menu that starts with ‘Bulk Actions’ and change this to ‘Regenerate Thumbnails’ and click on ‘Apply’.
Multiple Images Method 2: Go to media section and make sure you’re on the grid view. Click on the ‘Bulk Select’ button and click on the images you want to regenerate, then click on the the ‘Regenerate Thumbnails’ button.
All Images: Click on Regenerate Thumbnails in the admin menu, under Jixxio Media MGT and then click on the ‘Regenerate All Thumbnails’ button.