How can I allow students to use text box only inserted on a jpeg image but make jpeg image read only on Google Doc connected to Classroom?

I have inserted a jpeg image into a google doc and insert text box on that jpeg image by clicking on Insert->Drawing->New and then select the image from Computer and insert the text box where I need them by clicking on the Text Box and choose border color and copy paste them wherever I wanted them on Google Document.

Now I assign the google document on google classroom as an assignment. But how can I allow students to enter texts into text box only and not change the format, style and edit any other things on the jpeg image or change that file on Google Doc? How can I allow the students to use the text box only but view the jpeg file only?