When you say "my text field", I assume you mean the text from the page's CONTENT section? Try to upload the image into the folder, and then from the content editor, you can select image(s) to insert with the text:
If you don't want the uploaded image to be included in the automatically created gallery for the same page, you can click the HIDE (eye) icon on the image after uploading it.
Optionally, you can easily insert images into the text with basic HTML. For example:
<img src="/path/to/image.jpg">
Or inserting from the current dir, use the {{path}} var:
<img src="{{path}}imagefromthisdir.jpg">
Let me know how it works out.