Visit fourblogger.com for more wordpress and thesis tutorials. This video explains about the changing the default image size for thumbnail , medium and large image when we upload new image in wordpress post editor. wordpress post editor has 4 options to modify the uploaded image size. when we upload image in the post editor we have four options for alignment of the image like 1.none 2. left 3.center 4.right. similarly for the image size we have another four options to resize the image when we upload image in wordpress post editor. these four options as follows 1. thumbnail (size 150 x 150) 2. medium (max size 300 x 300) 3 .large (max size 1024 x 1024) 4. full size (original size of the image) depends on the option we have selected while upload each image size will we changed inside the post or page. we have a option to change the default size of the image options like thumbnail, medium and large. we can change these default sizes using the media link available under settings tab in the wordpress admin. here we can change any size for thumbnail, medium and large image. this will not affect the previously uploaded image. this size change only affects the new post images so we can change any size as per our post requirements.