Globally rewrite broken image links in node bodies
Assuming MySQL, you can fix that up with a search and replace SQL query.

Perhaps easiest from the MySQL command line, though could also use db_query.

The pattern is:

UPDATE tablename SET fieldname = REPLACE(fieldname, 'search', 'replace');


Something like:

UPDATE field_data_body SET body_value = REPLACE(body_value, 'sites/default/files/images/', 'sites/default/files/styles/[style]/public/images/');

UPDATE field_revision_body SET body_value = REPLACE(body_value, 'sites/default/files/images/', 'sites/default/files/styles/[style]/public/images/');


Backup the database first.

You may need to do it one image style at a time, or else make all the images uses a new standard style.

More info: http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_replace