Kristina
If you want to add text next to or underneath an image (Thumbnail) you would place it in a cell
For example you could insert a Table with 1 column and 2 rows
Insert your thumbnail in the first top row cell and place the text beneath it in the second row cell
You could adjust your table layot to accomodate your images and text
If you want text at an absolute position on or by an image, you would be better of doing that in a graphics program
Hope it helps
JDR