Click on pages
Click on Add New to add a new page / Click on edit on a page to update any of the pages

On the page that opens up, on the top left hand there is a Upload/Insert area
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Click on the image button image

A new popup will open up:

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CLick on select files and select the file to upload. This will start uploading the image, once the image is uploaded it will take you to this popup.
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Remove the link URL (so that the image doesn’t link to itself). Click on None to do this:
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Give it a SEO friendly title (currently it will be the image name, make it a description of the image, spaces are allowed)
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Leave alignment as None
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Select Full Size from the size menu
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Click on Insert into Post

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This will insert the image into the page or the post