Open the text editor (can be found in Items, Announcements, Discussion Board, Blogs, Journals, Wikis, Assignments and the Grade Centre).
Click on the 3 dots to expand the text editor.
Add file/s from harddrive
In the text editor, click on the Add content button.
Click on Insert Local Files.
Locate the appropriate image or images (for the latter, using Shift or Control on your keyboard then the left-click on your mouse allows multiple images to be selected).
Click on the Open button.
Add file/s from your course
In the text editor, click on the Add content button.
Click on Insert Course Files.
Browse the various files in your course and check the checkbox/es.